Dragomir Radev

Also published as: Dragomir R. Radev


2024

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ModeLing: A Novel Dataset for Testing Linguistic Reasoning in Language Models
Nathan Chi | Teodor Malchev | Riley Kong | Ryan Chi | Lucas Huang | Ethan Chi | R. McCoy | Dragomir Radev
Proceedings of the 6th Workshop on Research in Computational Linguistic Typology and Multilingual NLP

Large language models (LLMs) perform well on (at least) some evaluations of both few-shot multilingual adaptation and reasoning. However, evaluating the intersection of these two skills—multilingual few-shot reasoning—is difficult: even relatively low-resource languages can be found in large training corpora, raising the concern that when we intend to evaluate a model’s ability to generalize to a new language, that language may have in fact been present during the model’s training. If such language contamination has occurred, apparent cases of few-shot reasoning could actually be due to memorization. Towards understanding the capability of models to perform multilingual few-shot reasoning, we propose modeLing, a benchmark of Rosetta stone puzzles. This type of puzzle, originating from competitions called Linguistics Olympiads, contain a small number of sentences in a target language not previously known to the solver. Each sentence is translated to the solver’s language such that the provided sentence pairs uniquely specify a single most reasonable underlying set of rules; solving requires applying these rules to translate new expressions (Figure 1). modeLing languages are chosen to be extremely low-resource such that the risk of training data contamination is low, and unlike prior datasets, it consists entirely of problems written specifically for this work, as a further measure against data leakage. Empirically, we find evidence that popular LLMs do not have data leakage on our benchmark.

2023

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Logical Transformers: Infusing Logical Structures into Pre-Trained Language Models
Borui Wang | Qiuyuan Huang | Budhaditya Deb | Aaron Halfaker | Liqun Shao | Daniel McDuff | Ahmed Hassan Awadallah | Dragomir Radev | Jianfeng Gao
Findings of the Association for Computational Linguistics: ACL 2023

Natural language contains rich logical structures and logical information, and correctly detecting and accurately understanding these logical structures and information underlying natural language texts is very crucial for NLP models’ performance on many important NLU and NLG tasks. Existing pre-trained language models based on the transformer architecture mostly adopt a classical design for constructing their input embeddings that ignores the logical structures underlying natural language texts, thus limiting their ability to better capture and encode key logical information in the input sequences. To overcome such limitations, in this paper we first propose a novel approach to construct logic-aware input embeddings for transformer language models through a combination of logic detection, logic mapping and hierarchical logical projections, and then develop a corresponding new modeling paradigm that can upgrade existing transformer language models into logical transformers to boost their performance on different NLU and NLG tasks. Our empirical experiments on four important and challenging NLU and NLG tasks demonstrate that our proposed logical transformer language models can achieve superior performance over their baseline transformer models through a deeper understanding of the logical structures of texts.

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HPE: Answering Complex Questions over Text by Hybrid Question Parsing and Execution
Ye Liu | Semih Yavuz | Rui Meng | Dragomir Radev | Caiming Xiong | Shafiq Joty | Yingbo Zhou
Findings of the Association for Computational Linguistics: EMNLP 2023

The dominant paradigm of textual question answering systems is based on end-to-end neural networks, which excels at answering natural language questions but falls short on complex ones. This stands in contrast to the broad adaptation of semantic parsing approaches over structured data sources (e.g., relational database, knowledge graphs), that convert natural language questions to logical forms and execute them with query engines. Towards combining the strengths of neural and symbolic methods, we propose a framework of question parsing and execution on textual QA. It comprises two central pillars: (1) We parse the question of varying complexity into an intermediate representation, named H-expression, which is composed of simple questions as the primitives and symbolic operations representing the relationships among them; (2) To execute the resulting H-expressions, we design a hybrid executor, which integrates the deterministic rules to translate the symbolic operations with a drop-in neural reader network to answer each decomposed simple question. Hence, the proposed framework can be viewed as a top-down question parsing followed by a bottom-up answer backtracking. The resulting H-expressions closely guide the execution process, offering higher precision besides better interpretability while still preserving the advantages of the neural readers for resolving its primitive elements. Our extensive experiments on MuSiQue, 2WikiQA, HotpotQA, and NQ show that the proposed parsing and hybrid execution framework outperforms existing approaches in supervised, few-shot, and zero-shot settings, while also effectively exposing its underlying reasoning process.

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Enhancing Text-to-SQL Capabilities of Large Language Models: A Study on Prompt Design Strategies
Linyong Nan | Yilun Zhao | Weijin Zou | Narutatsu Ri | Jaesung Tae | Ellen Zhang | Arman Cohan | Dragomir Radev
Findings of the Association for Computational Linguistics: EMNLP 2023

In-context learning (ICL) has emerged as a new approach to various natural language processing tasks, utilizing large language models (LLMs) to make predictions based on context that has been supplemented with a few examples or task-specific instructions. In this paper, we aim to extend this method to question answering tasks that utilize structured knowledge sources, and improve Text-to-SQL systems by exploring various prompt design strategies for employing LLMs. We conduct a systematic investigation into different demonstration selection methods and optimal instruction formats for prompting LLMs in the Text-to-SQL task. Our approach involves leveraging the syntactic structure of an example’s SQL query to retrieve demonstrations, and we demonstrate that pursuing both diversity and similarity in demonstration selection leads to enhanced performance. Furthermore, we show that LLMs benefit from database-related knowledge augmentations. Our most effective strategy outperforms the state-of-the-art system by 2.5 points (Execution Accuracy) and the best fine-tuned system by 5.1 points on the Spider dataset. These results highlight the effectiveness of our approach in adapting LLMs to the Text-to-SQL task, and we present an analysis of the factors contributing to the success of our strategy.

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QTSumm: Query-Focused Summarization over Tabular Data
Yilun Zhao | Zhenting Qi | Linyong Nan | Boyu Mi | Yixin Liu | Weijin Zou | Simeng Han | Ruizhe Chen | Xiangru Tang | Yumo Xu | Dragomir Radev | Arman Cohan
Proceedings of the 2023 Conference on Empirical Methods in Natural Language Processing

People primarily consult tables to conduct data analysis or answer specific questions. Text generation systems that can provide accurate table summaries tailored to users’ information needs can facilitate more efficient access to relevant data insights. Motivated by this, we define a new query-focused table summarization task, where text generation models have to perform human-like reasoning and analysis over the given table to generate a tailored summary. We introduce a new benchmark named QTSumm for this task, which contains 7,111 human-annotated query-summary pairs over 2,934 tables covering diverse topics. We investigate a set of strong baselines on QTSumm, including text generation, table-to-text generation, and large language models. Experimental results and manual analysis reveal that the new task presents significant challenges in table-to-text generation for future research. Moreover, we propose a new approach named ReFactor, to retrieve and reason over query-relevant information from tabular data to generate several natural language facts. Experimental results demonstrate that ReFactor can bring effective improvements to baselines by concatenating the generated facts to the model input. Our data and code are publicly available at https://github.com/yale-nlp/QTSumm.

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Towards Interpretable and Efficient Automatic Reference-Based Summarization Evaluation
Yixin Liu | Alexander Fabbri | Yilun Zhao | Pengfei Liu | Shafiq Joty | Chien-Sheng Wu | Caiming Xiong | Dragomir Radev
Proceedings of the 2023 Conference on Empirical Methods in Natural Language Processing

Interpretability and efficiency are two important considerations for the adoption of neural automatic metrics. In this work, we develop strong-performing automatic metrics for reference-based summarization evaluation, based on a two-stage evaluation pipeline that first extracts basic information units from one text sequence and then checks the extracted units in another sequence. The metrics we developed include two-stage metrics that can provide high interpretability at both the fine-grained unit level and summary level, and one-stage metrics that achieve a balance between efficiency and interpretability. We make the developed tools publicly available at https://github.com/Yale-LILY/AutoACU.

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LoFT: Enhancing Faithfulness and Diversity for Table-to-Text Generation via Logic Form Control
Yilun Zhao | Zhenting Qi | Linyong Nan | Lorenzo Jaime Flores | Dragomir Radev
Proceedings of the 17th Conference of the European Chapter of the Association for Computational Linguistics

Logical Table-to-Text (LT2T) generation is tasked with generating logically faithful sentences from tables. There currently exists two challenges in the field: 1) Faithfulness: how to generate sentences that are factually correct given the table content; 2) Diversity: how to generate multiple sentences that offer different perspectives on the table. This work proposes LoFT, which utilizes logic forms as fact verifiers and content planners to control LT2T generation. Experimental results on the LogicNLG dataset demonstrate that LoFT is the first model that addresses unfaithfulness and lack of diversity issues simultaneously. Our code is publicly available at https://github.com/Yale-LILY/LoFT.

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A Transfer Learning Pipeline for Educational Resource Discovery with Application in Survey Generation
Irene Li | Thomas George | Alex Fabbri | Tammy Liao | Benjamin Chen | Rina Kawamura | Richard Zhou | Vanessa Yan | Swapnil Hingmire | Dragomir Radev
Proceedings of the 18th Workshop on Innovative Use of NLP for Building Educational Applications (BEA 2023)

Effective human learning depends on a wide selection of educational materials that align with the learner’s current understanding of the topic. While the Internet has revolutionized human learning or education, a substantial resource accessibility barrier still exists. Namely, the excess of online information can make it challenging to navigate and discover high-quality learning materials in a given subject area. In this paper, we propose an automatic pipeline for building an educational resource discovery system for new domains. The pipeline consists of three main steps: resource searching, feature extraction, and resource classification. We first collect frequent queries from a set of seed documents, and search the web with these queries to obtain candidate resources such as lecture slides and introductory blog posts. Then, we process these resources for BERT-based features and meta-features. Next, we train a tree-based classifier to decide whether they are suitable learning materials. The pipeline achieves F1 scores of 0.94 and 0.82 when evaluated on two similar but novel domains. Finally, we demonstrate how this pipeline can benefit two applications: prerequisite chain learning and leading paragraph generation for surveys. We also release a corpus of 39,728 manually labeled web resources and 659 queries from NLP, Computer Vision (CV), and Statistics (STATS).

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MACSum: Controllable Summarization with Mixed Attributes
Yusen Zhang | Yang Liu | Ziyi Yang | Yuwei Fang | Yulong Chen | Dragomir Radev | Chenguang Zhu | Michael Zeng | Rui Zhang
Transactions of the Association for Computational Linguistics, Volume 11

Controllable summarization allows users to generate customized summaries with specified attributes. However, due to the lack of designated annotations of controlled summaries, existing work has to craft pseudo datasets by adapting generic summarization benchmarks. Furthermore, most research focuses on controlling single attributes individually (e.g., a short summary or a highly abstractive summary) rather than controlling a mix of attributes together (e.g., a short and highly abstractive summary). In this paper, we propose MACSum, the first human-annotated summarization dataset for controlling mixed attributes. It contains source texts from two domains, news articles and dialogues, with human-annotated summaries controlled by five designed attributes (Length, Extractiveness, Specificity, Topic, and Speaker). We propose two simple and effective parameter-efficient approaches for the new task of mixed controllable summarization based on hard prompt tuning and soft prefix tuning. Results and analysis demonstrate that hard prompt models yield the best performance on most metrics and human evaluations. However, mixed-attribute control is still challenging for summarization tasks. Our dataset and code are available at https://github.com/psunlpgroup/MACSum.

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Revisiting the Gold Standard: Grounding Summarization Evaluation with Robust Human Evaluation
Yixin Liu | Alex Fabbri | Pengfei Liu | Yilun Zhao | Linyong Nan | Ruilin Han | Simeng Han | Shafiq Joty | Chien-Sheng Wu | Caiming Xiong | Dragomir Radev
Proceedings of the 61st Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)

Human evaluation is the foundation upon which the evaluation of both summarization systems and automatic metrics rests. However, existing human evaluation studies for summarization either exhibit a low inter-annotator agreement or have insufficient scale, and an in-depth analysis of human evaluation is lacking. Therefore, we address the shortcomings of existing summarization evaluation along the following axes: (1) We propose a modified summarization salience protocol, Atomic Content Units (ACUs), which is based on fine-grained semantic units and allows for a high inter-annotator agreement. (2) We curate the Robust Summarization Evaluation (RoSE) benchmark, a large human evaluation dataset consisting of 22,000 summary-level annotations over 28 top-performing systems on three datasets. (3) We conduct a comparative study of four human evaluation protocols, underscoring potential confounding factors in evaluation setups. (4) We evaluate 50 automatic metrics and their variants using the collected human annotations across evaluation protocols and demonstrate how our benchmark leads to more statistically stable and significant results. The metrics we benchmarked include recent methods based on large language models (LLMs), GPTScore and G-Eval. Furthermore, our findings have important implications for evaluating LLMs, as we show that LLMs adjusted by human feedback (e.g., GPT-3.5) may overfit unconstrained human evaluation, which is affected by the annotators’ prior, input-agnostic preferences, calling for more robust, targeted evaluation methods.

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RobuT: A Systematic Study of Table QA Robustness Against Human-Annotated Adversarial Perturbations
Yilun Zhao | Chen Zhao | Linyong Nan | Zhenting Qi | Wenlin Zhang | Xiangru Tang | Boyu Mi | Dragomir Radev
Proceedings of the 61st Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)

Despite significant progress having been made in question answering on tabular data (Table QA), it’s unclear whether, and to what extent existing Table QA models are robust to task-specific perturbations, e.g., replacing key question entities or shuffling table columns. To systematically study the robustness of Table QA models, we propose a benchmark called RobuT, which builds upon existing Table QA datasets (WTQ, WikiSQL-Weak, and SQA) and includes human-annotated adversarial perturbations in terms of table header, table content, and question. Our results indicate that both state-of-the-art Table QA models and large language models (e.g., GPT-3) with few-shot learning falter in these adversarial sets. We propose to address this problem by using large language models to generate adversarial examples to enhance training, which significantly improves the robustness of Table QA models.

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bgGLUE: A Bulgarian General Language Understanding Evaluation Benchmark
Momchil Hardalov | Pepa Atanasova | Todor Mihaylov | Galia Angelova | Kiril Simov | Petya Osenova | Veselin Stoyanov | Ivan Koychev | Preslav Nakov | Dragomir Radev
Proceedings of the 61st Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)

We present bgGLUE (Bulgarian General Language Understanding Evaluation), a benchmark for evaluating language models on Natural Language Understanding (NLU) tasks in Bulgarian. Our benchmark includes NLU tasks targeting a variety of NLP problems (e.g., natural language inference, fact-checking, named entity recognition, sentiment analysis, question answering, etc.) and machine learning tasks (sequence labeling, document-level classification, and regression). We run the first systematic evaluation of pre-trained language models for Bulgarian, comparing and contrasting results across the nine tasks in the benchmark. The evaluation results show strong performance on sequence labeling tasks, but there is a lot of room for improvement for tasks that require more complex reasoning. We make bgGLUE publicly available together with the fine-tuning and the evaluation code, as well as a public leaderboard at https://bgglue.github.io, and we hope that it will enable further advancements in developing NLU models for Bulgarian.

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BLOOM+1: Adding Language Support to BLOOM for Zero-Shot Prompting
Zheng Xin Yong | Hailey Schoelkopf | Niklas Muennighoff | Alham Fikri Aji | David Ifeoluwa Adelani | Khalid Almubarak | M Saiful Bari | Lintang Sutawika | Jungo Kasai | Ahmed Baruwa | Genta Winata | Stella Biderman | Edward Raff | Dragomir Radev | Vassilina Nikoulina
Proceedings of the 61st Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)

The BLOOM model is a large publicly available multilingual language model, but its pretraining was limited to 46 languages. To extend the benefits of BLOOM to other languages without incurring prohibitively large costs, it is desirable to adapt BLOOM to new languages not seen during pretraining. In this work, we apply existing language adaptation strategies to BLOOM and benchmark its zero-shot prompting performance on eight new languages in a resource-constrained setting. We find language adaptation to be effective at improving zero-shot performance in new languages. Surprisingly, we find that adapter-based finetuning is more effective than continued pretraining for large models. In addition, we discover that prompting performance is not significantly affected by language specifics, such as the writing system. It is primarily determined by the size of the language adaptation data. We also add new languages to BLOOMZ, which is a multitask finetuned version of BLOOM capable of following task instructions zero-shot. We find including a new language in the multitask fine-tuning mixture to be the most effective method to teach BLOOMZ a new language. We conclude that with sufficient training data language adaptation can generalize well to diverse languages. Our code is available at https://github.com/bigscience-workshop/multilingual-modeling.

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On Improving Summarization Factual Consistency from Natural Language Feedback
Yixin Liu | Budhaditya Deb | Milagro Teruel | Aaron Halfaker | Dragomir Radev | Ahmed Hassan Awadallah
Proceedings of the 61st Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)

Despite the recent progress in language generation models, their outputs may not always meet user expectations. In this work, we study whether informational feedback in natural language can be leveraged to improve generation quality and user preference alignment. To this end, we consider factual consistency in summarization, the quality that the summary should only contain information supported by the input documents, as the user-expected preference. We collect a high-quality dataset, DeFacto, containing human demonstrations and informational natural language feedback consisting of corrective instructions, edited summaries, and explanations with respect to the factual consistency of the summary. Using our dataset, we study three natural language generation tasks: (1) editing a summary by following the human feedback, (2) generating human feedback for editing the original summary, and (3) revising the initial summary to correct factual errors by generating both the human feedback and edited summary. We show that DeFacto can provide factually consistent human-edited summaries and further insights into summarization factual consistency thanks to its informational natural language feedback. We further demonstrate that fine-tuned language models can leverage our dataset to improve the summary factual consistency, while large language models lack the zero-shot learning ability in our proposed tasks that require controllable text generation.

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Crosslingual Generalization through Multitask Finetuning
Niklas Muennighoff | Thomas Wang | Lintang Sutawika | Adam Roberts | Stella Biderman | Teven Le Scao | M Saiful Bari | Sheng Shen | Zheng Xin Yong | Hailey Schoelkopf | Xiangru Tang | Dragomir Radev | Alham Fikri Aji | Khalid Almubarak | Samuel Albanie | Zaid Alyafeai | Albert Webson | Edward Raff | Colin Raffel
Proceedings of the 61st Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)

Multitask prompted finetuning (MTF) has been shown to help large language models generalize to new tasks in a zero-shot setting, but so far explorations of MTF have focused on English data and models. We apply MTF to the pretrained multilingual BLOOM and mT5 model families to produce finetuned variants called BLOOMZ and mT0. We find finetuning large multilingual language models on English tasks with English prompts allows for task genrealization to non-English languages that appear only in the pretraining corpus. Finetuning on multilingual tasks with English prompts further improves performance on English and non-English tasks leading to various state-of-the-art zero-shot results. We also investigate finetuning on multilingual tasks with prompts that have been machine-translated from English to match the language of each dataset. We find training on these machine-translated prompts leads to better performance on human-written prompts in the respective languages. Surprisingly, we find models are capable of zero-shot generalization to tasks in languages they have never intentionally seen. We conjecture that the models are learning higher-level capabilities that are both task- and language-agnostic. In addition, we introduce xP3, a composite of supervised datasets in 46 languages with English and machine-translated prompts. Our code, datasets and models are freely available at https://github.com/bigscience-workshop/xmtf.

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HiPool: Modeling Long Documents Using Graph Neural Networks
Irene Li | Aosong Feng | Dragomir Radev | Rex Ying
Proceedings of the 61st Annual Meeting of the Association for Computational Linguistics (Volume 2: Short Papers)

Encoding long sequences in Natural Language Processing (NLP) is a challenging problem. Though recent pretraining language models achieve satisfying performances in many NLP tasks, they are still restricted by a pre-defined maximum length, making them challenging to be extended to longer sequences. So some recent works utilize hierarchies to model long sequences. However, most of them apply sequential models for upper hierarchies, suffering from long dependency issues. In this paper, we alleviate these issues through a graph-based method. We first chunk the sequence with a fixed length to model the sentence-level information. We then leverage graphs to model intra- and cross-sentence correlations with a new attention mechanism. Additionally, due to limited standard benchmarks for long document classification (LDC), we propose a new challenging benchmark, totaling six datasets with up to 53k samples and 4034 average tokens’ length. Evaluation shows our model surpasses competitive baselines by 2.6% in F1 score, and 4.8% on the longest sequence dataset. Our method is shown to outperform hierarchical sequential models with better performance and scalability, especially for longer sequences.

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OpenRT: An Open-source Framework for Reasoning Over Tabular Data
Yilun Zhao | Boyu Mi | Zhenting Qi | Linyong Nan | Minghao Guo | Arman Cohan | Dragomir Radev
Proceedings of the 61st Annual Meeting of the Association for Computational Linguistics (Volume 3: System Demonstrations)

There are a growing number of table pre-training methods proposed for reasoning over tabular data (e.g., question answering, fact checking, and faithful text generation). However, most existing methods are benchmarked solely on a limited number of datasets, varying in configuration, which leads to a lack of unified, standardized, fair, and comprehensive comparison between methods. This paper presents OpenRT, the first open-source framework for reasoning over tabular data, to reproduce existing table pre-training models for performance comparison and develop new models quickly. We implemented and compared six table pre-training models on four question answering, one fact checking, and one faithful text generation datasets. Moreover, to enable the community to easily construct new table reasoning datasets, we developed TaRAT, an annotation tool which supports multi-person collaborative annotations for various kinds of table reasoning tasks. The researchers are able to deploy the newly-constructed dataset to OpenRT and compare the performances of different baseline systems.

2022

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FeTaQA: Free-form Table Question Answering
Linyong Nan | Chiachun Hsieh | Ziming Mao | Xi Victoria Lin | Neha Verma | Rui Zhang | Wojciech Kryściński | Hailey Schoelkopf | Riley Kong | Xiangru Tang | Mutethia Mutuma | Ben Rosand | Isabel Trindade | Renusree Bandaru | Jacob Cunningham | Caiming Xiong | Dragomir Radev | Dragomir Radev
Transactions of the Association for Computational Linguistics, Volume 10

Existing table question answering datasets contain abundant factual questions that primarily evaluate a QA system’s comprehension of query and tabular data. However, restricted by their short-form answers, these datasets fail to include question–answer interactions that represent more advanced and naturally occurring information needs: questions that ask for reasoning and integration of information pieces retrieved from a structured knowledge source. To complement the existing datasets and to reveal the challenging nature of the table-based question answering task, we introduce FeTaQA, a new dataset with 10K Wikipedia-based table, question, free-form answer, supporting table cells pairs. FeTaQA is collected from noteworthy descriptions of Wikipedia tables that contain information people tend to seek; generation of these descriptions requires advanced processing that humans perform on a daily basis: Understand the question and table, retrieve, integrate, infer, and conduct text planning and surface realization to generate an answer. We provide two benchmark methods for the proposed task: a pipeline method based on semantic parsing-based QA systems and an end-to-end method based on large pretrained text generation models, and show that FeTaQA poses a challenge for both methods.

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FeTaQA: Free-form Table Question Answering
Linyong Nan | Chiachun Hsieh | Ziming Mao | Xi Victoria Lin | Neha Verma | Rui Zhang | Wojciech Kryściński | Hailey Schoelkopf | Riley Kong | Xiangru Tang | Mutethia Mutuma | Ben Rosand | Isabel Trindade | Renusree Bandaru | Jacob Cunningham | Caiming Xiong | Dragomir Radev | Dragomir Radev
Transactions of the Association for Computational Linguistics, Volume 10

Existing table question answering datasets contain abundant factual questions that primarily evaluate a QA system’s comprehension of query and tabular data. However, restricted by their short-form answers, these datasets fail to include question–answer interactions that represent more advanced and naturally occurring information needs: questions that ask for reasoning and integration of information pieces retrieved from a structured knowledge source. To complement the existing datasets and to reveal the challenging nature of the table-based question answering task, we introduce FeTaQA, a new dataset with 10K Wikipedia-based table, question, free-form answer, supporting table cells pairs. FeTaQA is collected from noteworthy descriptions of Wikipedia tables that contain information people tend to seek; generation of these descriptions requires advanced processing that humans perform on a daily basis: Understand the question and table, retrieve, integrate, infer, and conduct text planning and surface realization to generate an answer. We provide two benchmark methods for the proposed task: a pipeline method based on semantic parsing-based QA systems and an end-to-end method based on large pretrained text generation models, and show that FeTaQA poses a challenge for both methods.

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BOOKSUM: A Collection of Datasets for Long-form Narrative Summarization
Wojciech Kryscinski | Nazneen Rajani | Divyansh Agarwal | Caiming Xiong | Dragomir Radev
Findings of the Association for Computational Linguistics: EMNLP 2022

The majority of existing text summarization datasets include short-form source documents that lack long-range causal and temporal dependencies, and often contain strong layout and stylistic biases. While relevant, such datasets will offer limited challenges for future text summarization systems. We address these issues by introducing BOOKSUM, a collection of datasets for long-form narrative summarization. Our dataset covers documents from the literature domain, such as novels, plays and stories, and includes highly abstractive, human written summaries on three levels of granularity of increasing difficulty: paragraph-, chapter-, and book-level. The domain and structure of our dataset poses a unique set of challenges for summarization systems, which include: processing very long documents, non-trivial causal and temporal dependencies, and rich discourse structures. To facilitate future work, we trained and evaluated multiple extractive and abstractive summarization models as baselines for our dataset.

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Look Ma, Only 400 Samples! Revisiting the Effectiveness of Automatic N-Gram Rule Generation for Spelling Normalization in Filipino
Lorenzo Jaime Flores | Dragomir Radev
Proceedings of The Third Workshop on Simple and Efficient Natural Language Processing (SustaiNLP)

With 84.75 million Filipinos online, the ability for models to process online text is crucial for developing Filipino NLP applications. To this end, spelling correction is a crucial preprocessing step for downstream processing. However, the lack of data prevents the use of language models for this task. In this paper, we propose an N-Gram + Damerau-Levenshtein distance model with automatic rule extraction. We train the model on 300 samples, and show that despite limited training data, it achieves good performance and outperforms other deep learning approaches in terms of accuracy and edit distance. Moreover, the model (1) requires little compute power, (2) trains in little time, thus allowing for retraining, and (3) is easily interpretable, allowing for direct troubleshooting, highlighting the success of traditional approaches over more complex deep learning models in settings where data is unavailable.

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Surfer100: Generating Surveys From Web Resources, Wikipedia-style
Irene Li | Alex Fabbri | Rina Kawamura | Yixin Liu | Xiangru Tang | Jaesung Tae | Chang Shen | Sally Ma | Tomoe Mizutani | Dragomir Radev
Proceedings of the Thirteenth Language Resources and Evaluation Conference

Fast-developing fields such as Artificial Intelligence (AI) often outpace the efforts of encyclopedic sources such as Wikipedia, which either do not completely cover recently-introduced topics or lack such content entirely. As a result, methods for automatically producing content are valuable tools to address this information overload. We show that recent advances in pretrained language modeling can be combined for a two-stage extractive and abstractive approach for Wikipedia lead paragraph generation. We extend this approach to generate longer Wikipedia-style summaries with sections and examine how such methods struggle in this application through detailed studies with 100 reference human-collected surveys. This is the first study on utilizing web resources for long Wikipedia-style summaries to the best of our knowledge.

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SummN: A Multi-Stage Summarization Framework for Long Input Dialogues and Documents
Yusen Zhang | Ansong Ni | Ziming Mao | Chen Henry Wu | Chenguang Zhu | Budhaditya Deb | Ahmed Awadallah | Dragomir Radev | Rui Zhang
Proceedings of the 60th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)

Text summarization helps readers capture salient information from documents, news, interviews, and meetings. However, most state-of-the-art pretrained language models (LM) are unable to efficiently process long text for many summarization tasks. In this paper, we propose SummN, a simple, flexible, and effective multi-stage framework for input texts that are longer than the maximum context length of typical pretrained LMs. SummN first splits the data samples and generates a coarse summary in multiple stages and then produces the final fine-grained summary based on it. Our framework can process input text of arbitrary length by adjusting the number of stages while keeping the LM input size fixed. Moreover, it can deal with both single-source documents and dialogues, and it can be used on top of different backbone abstractive summarization models. To the best of our knowledge, SummN is the first multi-stage split-then-summarize framework for long input summarization. Our experiments demonstrate that SummN outperforms previous state-of-the-art methods by improving ROUGE scores on three long meeting summarization datasets AMI, ICSI, and QMSum, two long TV series datasets from SummScreen, and a long document summarization dataset GovReport. Our data and code are available at https://github.com/psunlpgroup/Summ-N.

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DYLE: Dynamic Latent Extraction for Abstractive Long-Input Summarization
Ziming Mao | Chen Henry Wu | Ansong Ni | Yusen Zhang | Rui Zhang | Tao Yu | Budhaditya Deb | Chenguang Zhu | Ahmed Awadallah | Dragomir Radev
Proceedings of the 60th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)

Transformer-based models have achieved state-of-the-art performance on short-input summarization. However, they still struggle with summarizing longer text. In this paper, we present DYLE, a novel dynamic latent extraction approach for abstractive long-input summarization. DYLE jointly trains an extractor and a generator and treats the extracted text snippets as the latent variable, allowing dynamic snippet-level attention weights during decoding. To provide adequate supervision, we propose simple yet effective heuristics for oracle extraction as well as a consistency loss term, which encourages the extractor to approximate the averaged dynamic weights predicted by the generator. We evaluate our method on different long-document and long-dialogue summarization tasks: GovReport, QMSum, and arXiv. Experiment results show that DYLE outperforms all existing methods on GovReport and QMSum, with gains up to 6.1 ROUGE, while yielding strong results on arXiv. Further analysis shows that the proposed dynamic weights provide interpretability of our generation process.

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BRIO: Bringing Order to Abstractive Summarization
Yixin Liu | Pengfei Liu | Dragomir Radev | Graham Neubig
Proceedings of the 60th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)

Abstractive summarization models are commonly trained using maximum likelihood estimation, which assumes a deterministic (one-point) target distribution in which an ideal model will assign all the probability mass to the reference summary. This assumption may lead to performance degradation during inference, where the model needs to compare several system-generated (candidate) summaries that have deviated from the reference summary. To address this problem, we propose a novel training paradigm which assumes a non-deterministic distribution so that different candidate summaries are assigned probability mass according to their quality. Our method achieves a new state-of-the-art result on the CNN/DailyMail (47.78 ROUGE-1) and XSum (49.07 ROUGE-1) datasets. Further analysis also shows that our model can estimate probabilities of candidate summaries that are more correlated with their level of quality.

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PromptSource: An Integrated Development Environment and Repository for Natural Language Prompts
Stephen Bach | Victor Sanh | Zheng Xin Yong | Albert Webson | Colin Raffel | Nihal V. Nayak | Abheesht Sharma | Taewoon Kim | M Saiful Bari | Thibault Fevry | Zaid Alyafeai | Manan Dey | Andrea Santilli | Zhiqing Sun | Srulik Ben-david | Canwen Xu | Gunjan Chhablani | Han Wang | Jason Fries | Maged Al-shaibani | Shanya Sharma | Urmish Thakker | Khalid Almubarak | Xiangru Tang | Dragomir Radev | Mike Tian-jian Jiang | Alexander Rush
Proceedings of the 60th Annual Meeting of the Association for Computational Linguistics: System Demonstrations

PromptSource is a system for creating, sharing, and using natural language prompts. Prompts are functions that map an example from a dataset to a natural language input and target output. Using prompts to train and query language models is an emerging area in NLP that requires new tools that let users develop and refine these prompts collaboratively. PromptSource addresses the emergent challenges in this new setting with (1) a templating language for defining data-linked prompts, (2) an interface that lets users quickly iterate on prompt development by observing outputs of their prompts on many examples, and (3) a community-driven set of guidelines for contributing new prompts to a common pool. Over 2,000 prompts for roughly 170 datasets are already available in PromptSource. PromptSource is available at https://github.com/bigscience-workshop/promptsource.

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You reap what you sow: On the Challenges of Bias Evaluation Under Multilingual Settings
Zeerak Talat | Aurélie Névéol | Stella Biderman | Miruna Clinciu | Manan Dey | Shayne Longpre | Sasha Luccioni | Maraim Masoud | Margaret Mitchell | Dragomir Radev | Shanya Sharma | Arjun Subramonian | Jaesung Tae | Samson Tan | Deepak Tunuguntla | Oskar Van Der Wal
Proceedings of BigScience Episode #5 -- Workshop on Challenges & Perspectives in Creating Large Language Models

Evaluating bias, fairness, and social impact in monolingual language models is a difficult task. This challenge is further compounded when language modeling occurs in a multilingual context. Considering the implication of evaluation biases for large multilingual language models, we situate the discussion of bias evaluation within a wider context of social scientific research with computational work. We highlight three dimensions of developing multilingual bias evaluation frameworks: (1) increasing transparency through documentation, (2) expanding targets of bias beyond gender, and (3) addressing cultural differences that exist between languages. We further discuss the power dynamics and consequences of training large language models and recommend that researchers remain cognizant of the ramifications of developing such technologies.

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CONFIT: Toward Faithful Dialogue Summarization with Linguistically-Informed Contrastive Fine-tuning
Xiangru Tang | Arjun Nair | Borui Wang | Bingyao Wang | Jai Desai | Aaron Wade | Haoran Li | Asli Celikyilmaz | Yashar Mehdad | Dragomir Radev
Proceedings of the 2022 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies

Factual inconsistencies in generated summaries severely limit the practical applications of abstractive dialogue summarization. Although significant progress has been achieved by using pre-trained neural language models, substantial amounts of hallucinated content are found during the human evaluation. In this work, we first devised a typology of factual errors to better understand the types of hallucinations generated by current models and conducted human evaluation on popular dialog summarization dataset. We further propose a training strategy that improves the factual consistency and overall quality of summaries via a novel contrastive fine-tuning, called CONFIT. To tackle top factual errors from our annotation, we introduce additional contrastive loss with carefully designed hard negative samples and self-supervised dialogue-specific loss to capture the key information between speakers. We show that our model significantly reduces all kinds of factual errors on both SAMSum dialogue summarization and AMI meeting summarization. On both datasets, we achieve significant improvements over state-of-the-art baselines using both automatic metrics, ROUGE and BARTScore, and human evaluation.

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Investigating Crowdsourcing Protocols for Evaluating the Factual Consistency of Summaries
Xiangru Tang | Alexander Fabbri | Haoran Li | Ziming Mao | Griffin Adams | Borui Wang | Asli Celikyilmaz | Yashar Mehdad | Dragomir Radev
Proceedings of the 2022 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies

Current pre-trained models applied for summarization are prone to factual inconsistencies that misrepresent the source text. Evaluating the factual consistency of summaries is thus necessary to develop better models. However, the human evaluation setup for evaluating factual consistency has not been standardized. To determine the factors that affect the reliability of the human evaluation, we crowdsource evaluations for factual consistency across state-of-the-art models on two news summarization datasets using the rating-based Likert Scale and ranking-based Best-Worst Scaling. Our analysis reveals that the ranking-based Best-Worst Scaling offers a more reliable measure of summary quality across datasets and that the reliability of Likert ratings highly depends on the target dataset and the evaluation design. To improve crowdsourcing reliability, we extend the scale of the Likert rating and present a scoring algorithm for Best-Worst Scaling that we call value learning. Our crowdsourcing guidelines will be publicly available to facilitate future work on factual consistency in summarization.

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CREATIVESUMM: Shared Task on Automatic Summarization for Creative Writing
Divyansh Agarwal | Alexander R. Fabbri | Simeng Han | Wojciech Kryscinski | Faisal Ladhak | Bryan Li | Kathleen McKeown | Dragomir Radev | Tianyi Zhang | Sam Wiseman
Proceedings of The Workshop on Automatic Summarization for Creative Writing

This paper introduces the shared task of summrizing documents in several creative domains, namely literary texts, movie scripts, and television scripts. Summarizing these creative documents requires making complex literary interpretations, as well as understanding non-trivial temporal dependencies in texts containing varied styles of plot development and narrative structure. This poses unique challenges and is yet underexplored for text summarization systems. In this shared task, we introduce four sub-tasks and their corresponding datasets, focusing on summarizing books, movie scripts, primetime television scripts, and daytime soap opera scripts. We detail the process of curating these datasets for the task, as well as the metrics used for the evaluation of the submissions. As part of the CREATIVESUMM workshop at COLING 2022, the shared task attracted 18 submissions in total. We discuss the submissions and the baselines for each sub-task in this paper, along with directions for facilitating future work.

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UnifiedSKG: Unifying and Multi-Tasking Structured Knowledge Grounding with Text-to-Text Language Models
Tianbao Xie | Chen Henry Wu | Peng Shi | Ruiqi Zhong | Torsten Scholak | Michihiro Yasunaga | Chien-Sheng Wu | Ming Zhong | Pengcheng Yin | Sida I. Wang | Victor Zhong | Bailin Wang | Chengzu Li | Connor Boyle | Ansong Ni | Ziyu Yao | Dragomir Radev | Caiming Xiong | Lingpeng Kong | Rui Zhang | Noah A. Smith | Luke Zettlemoyer | Tao Yu
Proceedings of the 2022 Conference on Empirical Methods in Natural Language Processing

Structured knowledge grounding (SKG) leverages structured knowledge to complete user requests, such as semantic parsing over databases and question answering over knowledge bases. Since the inputs and outputs of SKG tasks are heterogeneous, they have been studied separately by different communities, which limits systematic and compatible research on SKG. In this paper, we overcome this limitation by proposing the UnifiedSKG framework, which unifies 21 SKG tasks into a text-to-text format, aiming to promote systematic SKG research, instead of being exclusive to a single task, domain, or dataset. We use UnifiedSKG to benchmark T5 with different sizes and show that T5, with simple modifications when necessary, achieves state-of-the-art performance on almost all of the 21 tasks. We further demonstrate that multi-task prefix-tuning improves the performance on most tasks, largely improving the overall performance. UnifiedSKG also facilitates the investigation of zero-shot and few-shot learning, and we show that T0, GPT-3, and Codex struggle in zero-shot and few-shot learning for SKG. We also use UnifiedSKG to conduct a series of controlled experiments on structured knowledge encoding variants across SKG tasks. UnifiedSKG is easily extensible to more tasks, and it is open-sourced at https://github.com/hkunlp/unifiedskg.

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Twist Decoding: Diverse Generators Guide Each Other
Jungo Kasai | Keisuke Sakaguchi | Ronan Le Bras | Hao Peng | Ximing Lu | Dragomir Radev | Yejin Choi | Noah A. Smith
Proceedings of the 2022 Conference on Empirical Methods in Natural Language Processing

Many language generation models are now available for a wide range of generation tasks, including machine translation and summarization. Combining such diverse models may lead to further progress, but ensembling generation models is challenging during inference: conventional ensembling methods (e.g., shallow fusion) require that the models share vocabulary/tokenization schemes. We introduce Twist decoding, a simple and general text generation algorithm that benefits from diverse models at inference time. Our method does not assume the vocabulary, tokenization or even generation order is shared. Our extensive evaluations on machine translation and scientific paper summarization demonstrate that Twist decoding substantially outperforms each model decoded in isolation over various scenarios, including cases where domain-specific and general-purpose models are both available. Twist decoding also consistently outperforms the popular reranking heuristic where output candidates from one model are rescored by another. We hope that our work will encourage researchers and practitioners to examine generation models collectively, not just independently, and to seek out models with complementary strengths to the currently available models.

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STRUDEL: Structured Dialogue Summarization for Dialogue Comprehension
Borui Wang | Chengcheng Feng | Arjun Nair | Madelyn Mao | Jai Desai | Asli Celikyilmaz | Haoran Li | Yashar Mehdad | Dragomir Radev
Proceedings of the 2022 Conference on Empirical Methods in Natural Language Processing

Abstractive dialogue summarization has long been viewed as an important standalone task in natural language processing, but no previous work has explored the possibility of whether abstractive dialogue summarization can also be used as a means to boost an NLP system’s performance on other important dialogue comprehension tasks. In this paper, we propose a novel type of dialogue summarization task - STRUctured DiaLoguE Summarization (STRUDEL) - that can help pre-trained language models to better understand dialogues and improve their performance on important dialogue comprehension tasks. In contrast to the holistic approach taken by the traditional free-form abstractive summarization task for dialogues, STRUDEL aims to decompose and imitate the hierarchical, systematic and structured mental process that we human beings usually go through when understanding and analyzing dialogues, and thus has the advantage of being more focused, specific and instructive for dialogue comprehension models to learn from. We further introduce a new STRUDEL dialogue comprehension modeling framework that integrates STRUDEL into a dialogue reasoning module over transformer encoder language models to improve their dialogue comprehension ability. In our empirical experiments on two important downstream dialogue comprehension tasks - dialogue question answering and dialogue response prediction - we demonstrate that our STRUDEL dialogue comprehension models can significantly improve the dialogue comprehension performance of transformer encoder language models.

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Leveraging Locality in Abstractive Text Summarization
Yixin Liu | Ansong Ni | Linyong Nan | Budhaditya Deb | Chenguang Zhu | Ahmed Hassan Awadallah | Dragomir Radev
Proceedings of the 2022 Conference on Empirical Methods in Natural Language Processing

Neural attention models have achieved significant improvements on many natural language processing tasks. However, the quadratic memory complexity of the self-attention module with respect to the input length hinders their applications in long text summarization. Instead of designing more efficient attention modules, we approach this problem by investigating if models with a restricted context can have competitive performance compared with the memory-efficient attention models that maintain a global context by treating the input as a single sequence. Our model is applied to individual pages, which contain parts of inputs grouped by the principle of locality, during both the encoding and decoding stages. We empirically investigated three kinds of locality in text summarization at different levels of granularity, ranging from sentences to documents. Our experimental results show that our model has a better performance compared with strong baseline models with efficient attention modules, and our analysis provides further insights into our locality-aware modeling strategy.

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R2D2: Robust Data-to-Text with Replacement Detection
Linyong Nan | Lorenzo Jaime Flores | Yilun Zhao | Yixin Liu | Luke Benson | Weijin Zou | Dragomir Radev
Proceedings of the 2022 Conference on Empirical Methods in Natural Language Processing

Unfaithful text generation is a common problem for text generation systems. In the case of Data-to-Text (D2T) systems, the factuality of the generated text is particularly crucial for any real-world applications. We introduce R2D2, a training framework that addresses unfaithful Data-to-Text generation by training a system both as a generator and a faithfulness discriminator with additional replacement detection and unlikelihood learning tasks. To facilitate such training, we propose two methods for sampling unfaithful sentences. We argue that the poor entity retrieval capability of D2T systems is one of the primary sources of unfaithfulness, so in addition to the existing metrics, we further propose named entity based metrics to evaluate the fidelity of D2T generations. Our experimental results show that R2D2 systems could effectively mitigate the unfaithful text generation, and they achieve new state-of-theart results on FeTaQA, LogicNLG, and ToTTo, all with significant improvements.

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Uni-Parser: Unified Semantic Parser for Question Answering on Knowledge Base and Database
Ye Liu | Semih Yavuz | Rui Meng | Dragomir Radev | Caiming Xiong | Yingbo Zhou
Proceedings of the 2022 Conference on Empirical Methods in Natural Language Processing

Parsing natural language questions into executable logical forms is a useful and interpretable way to perform question answering on structured data such as knowledge bases (KB) or databases (DB). However, existing approaches on semantic parsing cannot adapt to both modalities, as they suffer from the exponential growth of the logical form candidates and can hardly generalize to unseen data. In this work, we propose Uni-Parser, a unified semantic parser for question answering (QA) on both KB and DB. We define the primitive (relation and entity in KB, and table name, column name and cell value in DB) as the essential element in our framework. The number of primitives grows only at a linear rate to the number of retrieved relations in KB and DB, preventing us from exponential logic form candidates. We leverage the generator to predict final logical forms by altering and composing top-ranked primitives with different operations (e.g. select, where, count). With sufficiently pruned search space by a contrastive primitive ranker, the generator is empowered to capture the composition of primitives enhancing its generalization ability. We achieve competitive results on multiple KB and DB QA benchmarks with more efficiency, especially in the compositional and zero-shot settings.

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ReasTAP: Injecting Table Reasoning Skills During Pre-training via Synthetic Reasoning Examples
Yilun Zhao | Linyong Nan | Zhenting Qi | Rui Zhang | Dragomir Radev
Proceedings of the 2022 Conference on Empirical Methods in Natural Language Processing

Reasoning over tabular data requires both table structure understanding and a broad set of table reasoning skills. Current models with table-specific architectures and pre-training methods perform well on understanding table structures, but they still struggle with tasks that require various table reasoning skills. In this work, we develop ReasTAP to show that high-level table reasoning skills can be injected into models during pre-training without a complex table-specific architecture design. We define 7 table reasoning skills, such as numerical operation, temporal comparison, and conjunction. Each reasoning skill is associated with one example generator, which synthesizes questions over semi-structured tables according to the sampled templates. We model the table pre-training task as a sequence generation task and pre-train ReasTAP to generate precise answers of the synthetic examples. ReasTAP is evaluated on four benchmarks covering three downstream tasks including 1) WikiSQL-Weak and WikiTQ for Table Question Answering, 2) TabFact for Table Fact Verification, and 3) LogicNLG for Faithful Table-to-Text Generation. Experimental results demonstrate that ReasTAP achieves new state-of-the-art results on all of them and delivers a significant improvement under low-resource setting. Our code is publicly available at https://github.com/Yale-LILY/ReasTAP.

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GEMv2: Multilingual NLG Benchmarking in a Single Line of Code
Sebastian Gehrmann | Abhik Bhattacharjee | Abinaya Mahendiran | Alex Wang | Alexandros Papangelis | Aman Madaan | Angelina Mcmillan-major | Anna Shvets | Ashish Upadhyay | Bernd Bohnet | Bingsheng Yao | Bryan Wilie | Chandra Bhagavatula | Chaobin You | Craig Thomson | Cristina Garbacea | Dakuo Wang | Daniel Deutsch | Deyi Xiong | Di Jin | Dimitra Gkatzia | Dragomir Radev | Elizabeth Clark | Esin Durmus | Faisal Ladhak | Filip Ginter | Genta Indra Winata | Hendrik Strobelt | Hiroaki Hayashi | Jekaterina Novikova | Jenna Kanerva | Jenny Chim | Jiawei Zhou | Jordan Clive | Joshua Maynez | João Sedoc | Juraj Juraska | Kaustubh Dhole | Khyathi Raghavi Chandu | Laura Perez Beltrachini | Leonardo F . R. Ribeiro | Lewis Tunstall | Li Zhang | Mahim Pushkarna | Mathias Creutz | Michael White | Mihir Sanjay Kale | Moussa Kamal Eddine | Nico Daheim | Nishant Subramani | Ondrej Dusek | Paul Pu Liang | Pawan Sasanka Ammanamanchi | Qi Zhu | Ratish Puduppully | Reno Kriz | Rifat Shahriyar | Ronald Cardenas | Saad Mahamood | Salomey Osei | Samuel Cahyawijaya | Sanja Štajner | Sebastien Montella | Shailza Jolly | Simon Mille | Tahmid Hasan | Tianhao Shen | Tosin Adewumi | Vikas Raunak | Vipul Raheja | Vitaly Nikolaev | Vivian Tsai | Yacine Jernite | Ying Xu | Yisi Sang | Yixin Liu | Yufang Hou
Proceedings of the 2022 Conference on Empirical Methods in Natural Language Processing: System Demonstrations

Evaluations in machine learning rarely use the latest metrics, datasets, or human evaluation in favor of remaining compatible with prior work. The compatibility, often facilitated through leaderboards, thus leads to outdated but standardized evaluation practices. We pose that the standardization is taking place in the wrong spot. Evaluation infrastructure should enable researchers to use the latest methods and what should be standardized instead is how to incorporate these new evaluation advances. We introduce GEMv2, the new version of the Generation, Evaluation, and Metrics Benchmark which uses a modular infrastructure for dataset, model, and metric developers to benefit from each other’s work. GEMv2 supports 40 documented datasets in 51 languages, ongoing online evaluation for all datasets, and our interactive tools make it easier to add new datasets to the living benchmark.

2021

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Improving Cross-lingual Text Classification with Zero-shot Instance-Weighting
Irene Li | Prithviraj Sen | Huaiyu Zhu | Yunyao Li | Dragomir Radev
Proceedings of the 6th Workshop on Representation Learning for NLP (RepL4NLP-2021)

Cross-lingual text classification (CLTC) is a challenging task made even harder still due to the lack of labeled data in low-resource languages. In this paper, we propose zero-shot instance-weighting, a general model-agnostic zero-shot learning framework for improving CLTC by leveraging source instance weighting. It adds a module on top of pre-trained language models for similarity computation of instance weights, thus aligning each source instance to the target language. During training, the framework utilizes gradient descent that is weighted by instance weights to update parameters. We evaluate this framework over seven target languages on three fundamental tasks and show its effectiveness and extensibility, by improving on F1 score up to 4% in single-source transfer and 8% in multi-source transfer. To the best of our knowledge, our method is the first to apply instance weighting in zero-shot CLTC. It is simple yet effective and easily extensible into multi-source transfer.

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DocNLI: A Large-scale Dataset for Document-level Natural Language Inference
Wenpeng Yin | Dragomir Radev | Caiming Xiong
Findings of the Association for Computational Linguistics: ACL-IJCNLP 2021

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An Exploratory Study on Long Dialogue Summarization: What Works and What’s Next
Yusen Zhang | Ansong Ni | Tao Yu | Rui Zhang | Chenguang Zhu | Budhaditya Deb | Asli Celikyilmaz | Ahmed Hassan Awadallah | Dragomir Radev
Findings of the Association for Computational Linguistics: EMNLP 2021

Dialogue summarization helps readers capture salient information from long conversations in meetings, interviews, and TV series. However, real-world dialogues pose a great challenge to current summarization models, as the dialogue length typically exceeds the input limits imposed by recent transformer-based pre-trained models, and the interactive nature of dialogues makes relevant information more context-dependent and sparsely distributed than news articles. In this work, we perform a comprehensive study on long dialogue summarization by investigating three strategies to deal with the lengthy input problem and locate relevant information: (1) extended transformer models such as Longformer, (2) retrieve-then-summarize pipeline models with several dialogue utterance retrieval methods, and (3) hierarchical dialogue encoding models such as HMNet. Our experimental results on three long dialogue datasets (QMSum, MediaSum, SummScreen) show that the retrieve-then-summarize pipeline models yield the best performance. We also demonstrate that the summary quality can be further improved with a stronger retrieval model and pretraining on proper external summarization datasets.

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SummerTime: Text Summarization Toolkit for Non-experts
Ansong Ni | Zhangir Azerbayev | Mutethia Mutuma | Troy Feng | Yusen Zhang | Tao Yu | Ahmed Hassan Awadallah | Dragomir Radev
Proceedings of the 2021 Conference on Empirical Methods in Natural Language Processing: System Demonstrations

Recent advances in summarization provide models that can generate summaries of higher quality. Such models now exist for a number of summarization tasks, including query-based summarization, dialogue summarization, and multi-document summarization. While such models and tasks are rapidly growing in the research field, it has also become challenging for non-experts to keep track of them. To make summarization methods more accessible to a wider audience, we develop SummerTime by rethinking the summarization task from the perspective of an NLP non-expert. SummerTime is a complete toolkit for text summarization, including various models, datasets, and evaluation metrics, for a full spectrum of summarization-related tasks. SummerTime integrates with libraries designed for NLP researchers, and enables users with easy-to-use APIs. With SummerTime, users can locate pipeline solutions and search for the best model with their own data, and visualize the differences, all with a few lines of code. We also provide explanations for models and evaluation metrics to help users understand the model behaviors and select models that best suit their needs. Our library, along with a notebook demo, is available at https://github.com/Yale-LILY/SummerTime.

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DART: Open-Domain Structured Data Record to Text Generation
Linyong Nan | Dragomir Radev | Rui Zhang | Amrit Rau | Abhinand Sivaprasad | Chiachun Hsieh | Xiangru Tang | Aadit Vyas | Neha Verma | Pranav Krishna | Yangxiaokang Liu | Nadia Irwanto | Jessica Pan | Faiaz Rahman | Ahmad Zaidi | Mutethia Mutuma | Yasin Tarabar | Ankit Gupta | Tao Yu | Yi Chern Tan | Xi Victoria Lin | Caiming Xiong | Richard Socher | Nazneen Fatema Rajani
Proceedings of the 2021 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies

We present DART, an open domain structured DAta Record to Text generation dataset with over 82k instances (DARTs). Data-to-text annotations can be a costly process, especially when dealing with tables which are the major source of structured data and contain nontrivial structures. To this end, we propose a procedure of extracting semantic triples from tables that encodes their structures by exploiting the semantic dependencies among table headers and the table title. Our dataset construction framework effectively merged heterogeneous sources from open domain semantic parsing and spoken dialogue systems by utilizing techniques including tree ontology annotation, question-answer pair to declarative sentence conversion, and predicate unification, all with minimum post-editing. We present systematic evaluation on DART as well as new state-of-the-art results on WebNLG 2017 to show that DART (1) poses new challenges to existing data-to-text datasets and (2) facilitates out-of-domain generalization. Our data and code can be found at https://github.com/Yale-LILY/dart.

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Improving Zero and Few-Shot Abstractive Summarization with Intermediate Fine-tuning and Data Augmentation
Alexander Fabbri | Simeng Han | Haoyuan Li | Haoran Li | Marjan Ghazvininejad | Shafiq Joty | Dragomir Radev | Yashar Mehdad
Proceedings of the 2021 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies

Models pretrained with self-supervised objectives on large text corpora achieve state-of-the-art performance on English text summarization tasks. However, these models are typically fine-tuned on hundreds of thousands of data points, an infeasible requirement when applying summarization to new, niche domains. In this work, we introduce a novel and generalizable method, called WikiTransfer, for fine-tuning pretrained models for summarization in an unsupervised, dataset-specific manner. WikiTransfer fine-tunes pretrained models on pseudo-summaries, produced from generic Wikipedia data, which contain characteristics of the target dataset, such as the length and level of abstraction of the desired summaries. WikiTransfer models achieve state-of-the-art, zero-shot abstractive summarization performance on the CNN-DailyMail dataset and demonstrate the effectiveness of our approach on three additional diverse datasets. These models are more robust to noisy data and also achieve better or comparable few-shot performance using 10 and 100 training examples when compared to few-shot transfer from other summarization datasets. To further boost performance, we employ data augmentation via round-trip translation as well as introduce a regularization term for improved few-shot transfer. To understand the role of dataset aspects in transfer performance and the quality of the resulting output summaries, we further study the effect of the components of our unsupervised fine-tuning data and analyze few-shot performance using both automatic and human evaluation.

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QMSum: A New Benchmark for Query-based Multi-domain Meeting Summarization
Ming Zhong | Da Yin | Tao Yu | Ahmad Zaidi | Mutethia Mutuma | Rahul Jha | Ahmed Hassan Awadallah | Asli Celikyilmaz | Yang Liu | Xipeng Qiu | Dragomir Radev
Proceedings of the 2021 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies

Meetings are a key component of human collaboration. As increasing numbers of meetings are recorded and transcribed, meeting summaries have become essential to remind those who may or may not have attended the meetings about the key decisions made and the tasks to be completed. However, it is hard to create a single short summary that covers all the content of a long meeting involving multiple people and topics. In order to satisfy the needs of different types of users, we define a new query-based multi-domain meeting summarization task, where models have to select and summarize relevant spans of meetings in response to a query, and we introduce QMSum, a new benchmark for this task. QMSum consists of 1,808 query-summary pairs over 232 meetings in multiple domains. Besides, we investigate a locate-then-summarize method and evaluate a set of strong summarization baselines on the task. Experimental results and manual analysis reveal that QMSum presents significant challenges in long meeting summarization for future research. Dataset is available at https://github.com/Yale-LILY/QMSum.

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ConvoSumm: Conversation Summarization Benchmark and Improved Abstractive Summarization with Argument Mining
Alexander Fabbri | Faiaz Rahman | Imad Rizvi | Borui Wang | Haoran Li | Yashar Mehdad | Dragomir Radev
Proceedings of the 59th Annual Meeting of the Association for Computational Linguistics and the 11th International Joint Conference on Natural Language Processing (Volume 1: Long Papers)

While online conversations can cover a vast amount of information in many different formats, abstractive text summarization has primarily focused on modeling solely news articles. This research gap is due, in part, to the lack of standardized datasets for summarizing online discussions. To address this gap, we design annotation protocols motivated by an issues–viewpoints–assertions framework to crowdsource four new datasets on diverse online conversation forms of news comments, discussion forums, community question answering forums, and email threads. We benchmark state-of-the-art models on our datasets and analyze characteristics associated with the data. To create a comprehensive benchmark, we also evaluate these models on widely-used conversation summarization datasets to establish strong baselines in this domain. Furthermore, we incorporate argument mining through graph construction to directly model the issues, viewpoints, and assertions present in a conversation and filter noisy input, showing comparable or improved results according to automatic and human evaluations.

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Unsupervised Cross-Domain Prerequisite Chain Learning using Variational Graph Autoencoders
Irene Li | Vanessa Yan | Tianxiao Li | Rihao Qu | Dragomir Radev
Proceedings of the 59th Annual Meeting of the Association for Computational Linguistics and the 11th International Joint Conference on Natural Language Processing (Volume 2: Short Papers)

Learning prerequisite chains is an important task for one to pick up knowledge efficiently in both known and unknown domains. For example, one may be an expert in the natural language processing (NLP) domain, but want to determine the best order in which to learn new concepts in an unfamiliar Computer Vision domain (CV). Both domains share some common concepts, such as machine learning basics and deep learning models. In this paper, we solve the task of unsupervised cross-domain concept prerequisite chain learning, using an optimized variational graph autoencoder. Our model learns to transfer concept prerequisite relations from an information-rich domain (source domain) to an information-poor domain (target domain), substantially surpassing other baseline models. In addition, we expand an existing dataset by introducing two new domains—-CV and Bioinformatics (BIO). The annotated data and resources as well as the code will be made publicly available.

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SummEval: Re-evaluating Summarization Evaluation
Alexander R. Fabbri | Wojciech Kryściński | Bryan McCann | Caiming Xiong | Richard Socher | Dragomir Radev
Transactions of the Association for Computational Linguistics, Volume 9

The scarcity of comprehensive up-to-date studies on evaluation metrics for text summarization and the lack of consensus regarding evaluation protocols continue to inhibit progress. We address the existing shortcomings of summarization evaluation methods along five dimensions: 1) we re-evaluate 14 automatic evaluation metrics in a comprehensive and consistent fashion using neural summarization model outputs along with expert and crowd-sourced human annotations; 2) we consistently benchmark 23 recent summarization models using the aforementioned automatic evaluation metrics; 3) we assemble the largest collection of summaries generated by models trained on the CNN/DailyMail news dataset and share it in a unified format; 4) we implement and share a toolkit that provides an extensible and unified API for evaluating summarization models across a broad range of automatic metrics; and 5) we assemble and share the largest and most diverse, in terms of model types, collection of human judgments of model-generated summaries on the CNN/Daily Mail dataset annotated by both expert judges and crowd-source workers. We hope that this work will help promote a more complete evaluation protocol for text summarization as well as advance research in developing evaluation metrics that better correlate with human judgments.

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Testing Cross-Database Semantic Parsers With Canonical Utterances
Heather Lent | Semih Yavuz | Tao Yu | Tong Niu | Yingbo Zhou | Dragomir Radev | Xi Victoria Lin
Proceedings of the 2nd Workshop on Evaluation and Comparison of NLP Systems

The benchmark performance of cross-database semantic parsing has climbed steadily in recent years, catalyzed by the wide adoption of pre-trained language models. Yet existing work have shown that state-of-the-art cross-database semantic parsers struggle to generalize to novel user utterances, databases and query structures. To obtain transparent details on the strengths and limitation of these models, we propose a diagnostic testing approach based on controlled synthesis of canonical natural language and SQL pairs. Inspired by the CheckList, we characterize a set of essential capabilities for cross-database semantic parsing models, and detailed the method for synthesizing the corresponding test data. We evaluated a variety of high performing models using the proposed approach, and identified several non-obvious weaknesses across models (e.g. unable to correctly select many columns). Our dataset and code are released as a test suite at http://github.com/hclent/BehaviorCheckingSemPar.

2020

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Universal Natural Language Processing with Limited Annotations: Try Few-shot Textual Entailment as a Start
Wenpeng Yin | Nazneen Fatema Rajani | Dragomir Radev | Richard Socher | Caiming Xiong
Proceedings of the 2020 Conference on Empirical Methods in Natural Language Processing (EMNLP)

A standard way to address different NLP problems is by first constructing a problem-specific dataset, then building a model to fit this dataset. To build the ultimate artificial intelligence, we desire a single machine that can handle diverse new problems, for which task-specific annotations are limited. We bring up textual entailment as a unified solver for such NLP problems. However, current research of textual entailment has not spilled much ink on the following questions: (i) How well does a pretrained textual entailment system generalize across domains with only a handful of domain-specific examples? and (ii) When is it worth transforming an NLP task into textual entailment? We argue that the transforming is unnecessary if we can obtain rich annotations for this task. Textual entailment really matters particularly when the target NLP task has insufficient annotations. Universal NLP can be probably achieved through different routines. In this work, we introduce Universal Few-shot textual Entailment (UFO-Entail). We demonstrate that this framework enables a pretrained entailment model to work well on new entailment domains in a few-shot setting, and show its effectiveness as a unified solver for several downstream NLP tasks such as question answering and coreference resolution when the end-task annotations are limited.

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ESPRIT: Explaining Solutions to Physical Reasoning Tasks
Nazneen Fatema Rajani | Rui Zhang | Yi Chern Tan | Stephan Zheng | Jeremy Weiss | Aadit Vyas | Abhijit Gupta | Caiming Xiong | Richard Socher | Dragomir Radev
Proceedings of the 58th Annual Meeting of the Association for Computational Linguistics

Neural networks lack the ability to reason about qualitative physics and so cannot generalize to scenarios and tasks unseen during training. We propose ESPRIT, a framework for commonsense reasoning about qualitative physics in natural language that generates interpretable descriptions of physical events. We use a two-step approach of first identifying the pivotal physical events in an environment and then generating natural language descriptions of those events using a data-to-text approach. Our framework learns to generate explanations of how the physical simulation will causally evolve so that an agent or a human can easily reason about a solution using those interpretable descriptions. Human evaluations indicate that ESPRIT produces crucial fine-grained details and has high coverage of physical concepts compared to even human annotations. Dataset, code and documentation are available at https://github.com/salesforce/esprit.

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R-VGAE: Relational-variational Graph Autoencoder for Unsupervised Prerequisite Chain Learning
Irene Li | Alexander Fabbri | Swapnil Hingmire | Dragomir Radev
Proceedings of the 28th International Conference on Computational Linguistics

The task of concept prerequisite chain learning is to automatically determine the existence of prerequisite relationships among concept pairs. In this paper, we frame learning prerequisite relationships among concepts as an unsupervised task with no access to labeled concept pairs during training. We propose a model called the Relational-Variational Graph AutoEncoder (R-VGAE) to predict concept relations within a graph consisting of concept and resource nodes. Results show that our unsupervised approach outperforms graph-based semi-supervised methods and other baseline methods by up to 9.77% and 10.47% in terms of prerequisite relation prediction accuracy and F1 score. Our method is notably the first graph-based model that attempts to make use of deep learning representations for the task of unsupervised prerequisite learning. We also expand an existing corpus which totals 1,717 English Natural Language Processing (NLP)-related lecture slide files and manual concept pair annotations over 322 topics.

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Proceedings of the First Workshop on Interactive and Executable Semantic Parsing
Ben Bogin | Srinivasan Iyer | Xi Victoria Lin | Dragomir Radev | Alane Suhr | Panupong | Caiming Xiong | Pengcheng Yin | Tao Yu | Rui Zhang | Victor Zhong
Proceedings of the First Workshop on Interactive and Executable Semantic Parsing

2019

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Multi-News: A Large-Scale Multi-Document Summarization Dataset and Abstractive Hierarchical Model
Alexander Fabbri | Irene Li | Tianwei She | Suyi Li | Dragomir Radev
Proceedings of the 57th Annual Meeting of the Association for Computational Linguistics

Automatic generation of summaries from multiple news articles is a valuable tool as the number of online publications grows rapidly. Single document summarization (SDS) systems have benefited from advances in neural encoder-decoder model thanks to the availability of large datasets. However, multi-document summarization (MDS) of news articles has been limited to datasets of a couple of hundred examples. In this paper, we introduce Multi-News, the first large-scale MDS news dataset. Additionally, we propose an end-to-end model which incorporates a traditional extractive summarization model with a standard SDS model and achieves competitive results on MDS datasets. We benchmark several methods on Multi-News and hope that this work will promote advances in summarization in the multi-document setting.

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Improving Low-Resource Cross-lingual Document Retrieval by Reranking with Deep Bilingual Representations
Rui Zhang | Caitlin Westerfield | Sungrok Shim | Garrett Bingham | Alexander Fabbri | William Hu | Neha Verma | Dragomir Radev
Proceedings of the 57th Annual Meeting of the Association for Computational Linguistics

In this paper, we propose to boost low-resource cross-lingual document retrieval performance with deep bilingual query-document representations. We match queries and documents in both source and target languages with four components, each of which is implemented as a term interaction-based deep neural network with cross-lingual word embeddings as input. By including query likelihood scores as extra features, our model effectively learns to rerank the retrieved documents by using a small number of relevance labels for low-resource language pairs. Due to the shared cross-lingual word embedding space, the model can also be directly applied to another language pair without any training label. Experimental results on the Material dataset show that our model outperforms the competitive translation-based baselines on English-Swahili, English-Tagalog, and English-Somali cross-lingual information retrieval tasks.

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SParC: Cross-Domain Semantic Parsing in Context
Tao Yu | Rui Zhang | Michihiro Yasunaga | Yi Chern Tan | Xi Victoria Lin | Suyi Li | Heyang Er | Irene Li | Bo Pang | Tao Chen | Emily Ji | Shreya Dixit | David Proctor | Sungrok Shim | Jonathan Kraft | Vincent Zhang | Caiming Xiong | Richard Socher | Dragomir Radev
Proceedings of the 57th Annual Meeting of the Association for Computational Linguistics

We present SParC, a dataset for cross-domainSemanticParsing inContext that consists of 4,298 coherent question sequences (12k+ individual questions annotated with SQL queries). It is obtained from controlled user interactions with 200 complex databases over 138 domains. We provide an in-depth analysis of SParC and show that it introduces new challenges compared to existing datasets. SParC demonstrates complex contextual dependencies, (2) has greater semantic diversity, and (3) requires generalization to unseen domains due to its cross-domain nature and the unseen databases at test time. We experiment with two state-of-the-art text-to-SQL models adapted to the context-dependent, cross-domain setup. The best model obtains an exact match accuracy of 20.2% over all questions and less than10% over all interaction sequences, indicating that the cross-domain setting and the con-textual phenomena of the dataset present significant challenges for future research. The dataset, baselines, and leaderboard are released at https://yale-lily.github.io/sparc.

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Syntax-aware Neural Semantic Role Labeling with Supertags
Jungo Kasai | Dan Friedman | Robert Frank | Dragomir Radev | Owen Rambow
Proceedings of the 2019 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies, Volume 1 (Long and Short Papers)

We introduce a new syntax-aware model for dependency-based semantic role labeling that outperforms syntax-agnostic models for English and Spanish. We use a BiLSTM to tag the text with supertags extracted from dependency parses, and we feed these supertags, along with words and parts of speech, into a deep highway BiLSTM for semantic role labeling. Our model combines the strengths of earlier models that performed SRL on the basis of a full dependency parse with more recent models that use no syntactic information at all. Our local and non-ensemble model achieves state-of-the-art performance on the CoNLL 09 English and Spanish datasets. SRL models benefit from syntactic information, and we show that supertagging is a simple, powerful, and robust way to incorporate syntax into a neural SRL system.

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CoSQL: A Conversational Text-to-SQL Challenge Towards Cross-Domain Natural Language Interfaces to Databases
Tao Yu | Rui Zhang | Heyang Er | Suyi Li | Eric Xue | Bo Pang | Xi Victoria Lin | Yi Chern Tan | Tianze Shi | Zihan Li | Youxuan Jiang | Michihiro Yasunaga | Sungrok Shim | Tao Chen | Alexander Fabbri | Zifan Li | Luyao Chen | Yuwen Zhang | Shreya Dixit | Vincent Zhang | Caiming Xiong | Richard Socher | Walter Lasecki | Dragomir Radev
Proceedings of the 2019 Conference on Empirical Methods in Natural Language Processing and the 9th International Joint Conference on Natural Language Processing (EMNLP-IJCNLP)

We present CoSQL, a corpus for building cross-domain, general-purpose database (DB) querying dialogue systems. It consists of 30k+ turns plus 10k+ annotated SQL queries, obtained from a Wizard-of-Oz (WOZ) collection of 3k dialogues querying 200 complex DBs spanning 138 domains. Each dialogue simulates a real-world DB query scenario with a crowd worker as a user exploring the DB and a SQL expert retrieving answers with SQL, clarifying ambiguous questions, or otherwise informing of unanswerable questions. When user questions are answerable by SQL, the expert describes the SQL and execution results to the user, hence maintaining a natural interaction flow. CoSQL introduces new challenges compared to existing task-oriented dialogue datasets: (1) the dialogue states are grounded in SQL, a domain-independent executable representation, instead of domain-specific slot value pairs, and (2) because testing is done on unseen databases, success requires generalizing to new domains. CoSQL includes three tasks: SQL-grounded dialogue state tracking, response generation from query results, and user dialogue act prediction. We evaluate a set of strong baselines for each task and show that CoSQL presents significant challenges for future research. The dataset, baselines, and leaderboard will be released at https://yale-lily.github.io/cosql.

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Editing-Based SQL Query Generation for Cross-Domain Context-Dependent Questions
Rui Zhang | Tao Yu | Heyang Er | Sungrok Shim | Eric Xue | Xi Victoria Lin | Tianze Shi | Caiming Xiong | Richard Socher | Dragomir Radev
Proceedings of the 2019 Conference on Empirical Methods in Natural Language Processing and the 9th International Joint Conference on Natural Language Processing (EMNLP-IJCNLP)

We focus on the cross-domain context-dependent text-to-SQL generation task. Based on the observation that adjacent natural language questions are often linguistically dependent and their corresponding SQL queries tend to overlap, we utilize the interaction history by editing the previous predicted query to improve the generation quality. Our editing mechanism views SQL as sequences and reuses generation results at the token level in a simple manner. It is flexible to change individual tokens and robust to error propagation. Furthermore, to deal with complex table structures in different domains, we employ an utterance-table encoder and a table-aware decoder to incorporate the context of the user utterance and the table schema. We evaluate our approach on the SParC dataset and demonstrate the benefit of editing compared with the state-of-the-art baselines which generate SQL from scratch. Our code is available at https://github.com/ryanzhumich/sparc_atis_pytorch.

2018

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SyntaxSQLNet: Syntax Tree Networks for Complex and Cross-Domain Text-to-SQL Task
Tao Yu | Michihiro Yasunaga | Kai Yang | Rui Zhang | Dongxu Wang | Zifan Li | Dragomir Radev
Proceedings of the 2018 Conference on Empirical Methods in Natural Language Processing

Most existing studies in text-to-SQL tasks do not require generating complex SQL queries with multiple clauses or sub-queries, and generalizing to new, unseen databases. In this paper we propose SyntaxSQLNet, a syntax tree network to address the complex and cross-domain text-to-SQL generation task. SyntaxSQLNet employs a SQL specific syntax tree-based decoder with SQL generation path history and table-aware column attention encoders. We evaluate SyntaxSQLNet on a new large-scale text-to-SQL corpus containing databases with multiple tables and complex SQL queries containing multiple SQL clauses and nested queries. We use a database split setting where databases in the test set are unseen during training. Experimental results show that SyntaxSQLNet can handle a significantly greater number of complex SQL examples than prior work, outperforming the previous state-of-the-art model by 9.5% in exact matching accuracy. To our knowledge, we are the first to study this complex text-to-SQL task. Our task and models with the latest updates are available at https://yale-lily.github.io/seq2sql/spider.

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Spider: A Large-Scale Human-Labeled Dataset for Complex and Cross-Domain Semantic Parsing and Text-to-SQL Task
Tao Yu | Rui Zhang | Kai Yang | Michihiro Yasunaga | Dongxu Wang | Zifan Li | James Ma | Irene Li | Qingning Yao | Shanelle Roman | Zilin Zhang | Dragomir Radev
Proceedings of the 2018 Conference on Empirical Methods in Natural Language Processing

We present Spider, a large-scale complex and cross-domain semantic parsing and text-to-SQL dataset annotated by 11 college students. It consists of 10,181 questions and 5,693 unique complex SQL queries on 200 databases with multiple tables covering 138 different domains. We define a new complex and cross-domain semantic parsing and text-to-SQL task so that different complicated SQL queries and databases appear in train and test sets. In this way, the task requires the model to generalize well to both new SQL queries and new database schemas. Therefore, Spider is distinct from most of the previous semantic parsing tasks because they all use a single database and have the exact same program in the train set and the test set. We experiment with various state-of-the-art models and the best model achieves only 9.7% exact matching accuracy on a database split setting. This shows that Spider presents a strong challenge for future research. Our dataset and task with the most recent updates are publicly available at https://yale-lily.github.io/seq2sql/spider.

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Robust Multilingual Part-of-Speech Tagging via Adversarial Training
Michihiro Yasunaga | Jungo Kasai | Dragomir Radev
Proceedings of the 2018 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies, Volume 1 (Long Papers)

Adversarial training (AT) is a powerful regularization method for neural networks, aiming to achieve robustness to input perturbations. Yet, the specific effects of the robustness obtained from AT are still unclear in the context of natural language processing. In this paper, we propose and analyze a neural POS tagging model that exploits AT. In our experiments on the Penn Treebank WSJ corpus and the Universal Dependencies (UD) dataset (27 languages), we find that AT not only improves the overall tagging accuracy, but also 1) prevents over-fitting well in low resource languages and 2) boosts tagging accuracy for rare / unseen words. We also demonstrate that 3) the improved tagging performance by AT contributes to the downstream task of dependency parsing, and that 4) AT helps the model to learn cleaner word representations. 5) The proposed AT model is generally effective in different sequence labeling tasks. These positive results motivate further use of AT for natural language tasks.

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TypeSQL: Knowledge-Based Type-Aware Neural Text-to-SQL Generation
Tao Yu | Zifan Li | Zilin Zhang | Rui Zhang | Dragomir Radev
Proceedings of the 2018 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies, Volume 2 (Short Papers)

Interacting with relational databases through natural language helps users with any background easily query and analyze a vast amount of data. This requires a system that understands users’ questions and converts them to SQL queries automatically. In this paper, we present a novel approach TypeSQL which formats the problem as a slot filling task in a more reasonable way. In addition, TypeSQL utilizes type information to better understand rare entities and numbers in the questions. We experiment this idea on the WikiSQL dataset and outperform the prior art by 6% in much shorter time. We also show that accessing the content of databases can significantly improve the performance when users’ queries are not well-formed. TypeSQL can reach 82.6% accuracy, a 17.5% absolute improvement compared to the previous content-sensitive model.

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Improving Text-to-SQL Evaluation Methodology
Catherine Finegan-Dollak | Jonathan K. Kummerfeld | Li Zhang | Karthik Ramanathan | Sesh Sadasivam | Rui Zhang | Dragomir Radev
Proceedings of the 56th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)

To be informative, an evaluation must measure how well systems generalize to realistic unseen data. We identify limitations of and propose improvements to current evaluations of text-to-SQL systems. First, we compare human-generated and automatically generated questions, characterizing properties of queries necessary for real-world applications. To facilitate evaluation on multiple datasets, we release standardized and improved versions of seven existing datasets and one new text-to-SQL dataset. Second, we show that the current division of data into training and test sets measures robustness to variations in the way questions are asked, but only partially tests how well systems generalize to new queries; therefore, we propose a complementary dataset split for evaluation of future work. Finally, we demonstrate how the common practice of anonymizing variables during evaluation removes an important challenge of the task. Our observations highlight key difficulties, and our methodology enables effective measurement of future development.

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TutorialBank: A Manually-Collected Corpus for Prerequisite Chains, Survey Extraction and Resource Recommendation
Alexander Fabbri | Irene Li | Prawat Trairatvorakul | Yijiao He | Weitai Ting | Robert Tung | Caitlin Westerfield | Dragomir Radev
Proceedings of the 56th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)

The field of Natural Language Processing (NLP) is growing rapidly, with new research published daily along with an abundance of tutorials, codebases and other online resources. In order to learn this dynamic field or stay up-to-date on the latest research, students as well as educators and researchers must constantly sift through multiple sources to find valuable, relevant information. To address this situation, we introduce TutorialBank, a new, publicly available dataset which aims to facilitate NLP education and research. We have manually collected and categorized over 5,600 resources on NLP as well as the related fields of Artificial Intelligence (AI), Machine Learning (ML) and Information Retrieval (IR). Our dataset is notably the largest manually-picked corpus of resources intended for NLP education which does not include only academic papers. Additionally, we have created both a search engine and a command-line tool for the resources and have annotated the corpus to include lists of research topics, relevant resources for each topic, prerequisite relations among topics, relevant sub-parts of individual resources, among other annotations. We are releasing the dataset and present several avenues for further research.

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Neural Coreference Resolution with Deep Biaffine Attention by Joint Mention Detection and Mention Clustering
Rui Zhang | Cícero Nogueira dos Santos | Michihiro Yasunaga | Bing Xiang | Dragomir Radev
Proceedings of the 56th Annual Meeting of the Association for Computational Linguistics (Volume 2: Short Papers)

Coreference resolution aims to identify in a text all mentions that refer to the same real world entity. The state-of-the-art end-to-end neural coreference model considers all text spans in a document as potential mentions and learns to link an antecedent for each possible mention. In this paper, we propose to improve the end-to-end coreference resolution system by (1) using a biaffine attention model to get antecedent scores for each possible mention, and (2) jointly optimizing the mention detection accuracy and mention clustering accuracy given the mention cluster labels. Our model achieves the state-of-the-art performance on the CoNLL-2012 shared task English test set.

2017

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Graph-based Neural Multi-Document Summarization
Michihiro Yasunaga | Rui Zhang | Kshitijh Meelu | Ayush Pareek | Krishnan Srinivasan | Dragomir Radev
Proceedings of the 21st Conference on Computational Natural Language Learning (CoNLL 2017)

We propose a neural multi-document summarization system that incorporates sentence relation graphs. We employ a Graph Convolutional Network (GCN) on the relation graphs, with sentence embeddings obtained from Recurrent Neural Networks as input node features. Through multiple layer-wise propagation, the GCN generates high-level hidden sentence features for salience estimation. We then use a greedy heuristic to extract salient sentences that avoid redundancy. In our experiments on DUC 2004, we consider three types of sentence relation graphs and demonstrate the advantage of combining sentence relations in graphs with the representation power of deep neural networks. Our model improves upon other traditional graph-based extractive approaches and the vanilla GRU sequence model with no graph, and it achieves competitive results against other state-of-the-art multi-document summarization systems.

2016

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Humor in Collective Discourse: Unsupervised Funniness Detection in the New Yorker Cartoon Caption Contest
Dragomir Radev | Amanda Stent | Joel Tetreault | Aasish Pappu | Aikaterini Iliakopoulou | Agustin Chanfreau | Paloma de Juan | Jordi Vallmitjana | Alejandro Jaimes | Rahul Jha | Robert Mankoff
Proceedings of the Tenth International Conference on Language Resources and Evaluation (LREC'16)

The New Yorker publishes a weekly captionless cartoon. More than 5,000 readers submit captions for it. The editors select three of them and ask the readers to pick the funniest one. We describe an experiment that compares a dozen automatic methods for selecting the funniest caption. We show that negative sentiment, human-centeredness, and lexical centrality most strongly match the funniest captions, followed by positive sentiment. These results are useful for understanding humor and also in the design of more engaging conversational agents in text and multimodal (vision+text) systems. As part of this work, a large set of cartoons and captions is being made available to the community.

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Sentence Similarity based on Dependency Tree Kernels for Multi-document Summarization
Şaziye Betül Özateş | Arzucan Özgür | Dragomir Radev
Proceedings of the Tenth International Conference on Language Resources and Evaluation (LREC'16)

We introduce an approach based on using the dependency grammar representations of sentences to compute sentence similarity for extractive multi-document summarization. We adapt and investigate the effects of two untyped dependency tree kernels, which have originally been proposed for relation extraction, to the multi-document summarization problem. In addition, we propose a series of novel dependency grammar based kernels to better represent the syntactic and semantic similarities among the sentences. The proposed methods incorporate the type information of the dependency relations for sentence similarity calculation. To our knowledge, this is the first study that investigates using dependency tree based sentence similarity for multi-document summarization.

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Extractive Summarization under Strict Length Constraints
Yashar Mehdad | Amanda Stent | Kapil Thadani | Dragomir Radev | Youssef Billawala | Karolina Buchner
Proceedings of the Tenth International Conference on Language Resources and Evaluation (LREC'16)

In this paper we report a comparison of various techniques for single-document extractive summarization under strict length budgets, which is a common commercial use case (e.g. summarization of news articles by news aggregators). We show that, evaluated using ROUGE, numerous algorithms from the literature fail to beat a simple lead-based baseline for this task. However, a supervised approach with lightweight and efficient features improves over the lead-based baseline. Additional human evaluation demonstrates that the supervised approach also performs competitively with a commercial system that uses more sophisticated features.

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A Low-Rank Approximation Approach to Learning Joint Embeddings of News Stories and Images for Timeline Summarization
William Yang Wang | Yashar Mehdad | Dragomir R. Radev | Amanda Stent
Proceedings of the 2016 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies

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Dependency Sensitive Convolutional Neural Networks for Modeling Sentences and Documents
Rui Zhang | Honglak Lee | Dragomir R. Radev
Proceedings of the 2016 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies

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Effects of Creativity and Cluster Tightness on Short Text Clustering Performance
Catherine Finegan-Dollak | Reed Coke | Rui Zhang | Xiangyi Ye | Dragomir Radev
Proceedings of the 54th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)

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Nested Propositions in Open Information Extraction
Nikita Bhutani | H. V. Jagadish | Dragomir Radev
Proceedings of the 2016 Conference on Empirical Methods in Natural Language Processing

2015

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Content Models for Survey Generation: A Factoid-Based Evaluation
Rahul Jha | Catherine Finegan-Dollak | Ben King | Reed Coke | Dragomir Radev
Proceedings of the 53rd Annual Meeting of the Association for Computational Linguistics and the 7th International Joint Conference on Natural Language Processing (Volume 1: Long Papers)

2014

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Experiments in Sentence Language Identification with Groups of Similar Languages
Ben King | Dragomir Radev | Steven Abney
Proceedings of the First Workshop on Applying NLP Tools to Similar Languages, Varieties and Dialects

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A Random Walk–Based Model for Identifying Semantic Orientation
Ahmed Hassan | Amjad Abu-Jbara | Wanchen Lu | Dragomir Radev
Computational Linguistics, Volume 40, Issue 3 - September 2014

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Heterogeneous Networks and Their Applications: Scientometrics, Name Disambiguation, and Topic Modeling
Ben King | Rahul Jha | Dragomir R. Radev
Transactions of the Association for Computational Linguistics, Volume 2

We present heterogeneous networks as a way to unify lexical networks with relational data. We build a unified ACL Anthology network, tying together the citation, author collaboration, and term-cooccurence networks with affiliation and venue relations. This representation proves to be convenient and allows problems such as name disambiguation, topic modeling, and the measurement of scientific impact to be easily solved using only this network and off-the-shelf graph algorithms.

2013

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Purpose and Polarity of Citation: Towards NLP-based Bibliometrics
Amjad Abu-Jbara | Jefferson Ezra | Dragomir Radev
Proceedings of the 2013 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies

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Experimental Results on the Native Language Identification Shared Task
Amjad Abu-Jbara | Rahul Jha | Eric Morley | Dragomir Radev
Proceedings of the Eighth Workshop on Innovative Use of NLP for Building Educational Applications

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Proceedings of the Fourth Workshop on Teaching NLP and CL
Ivan Derzhanski | Dragomir Radev
Proceedings of the Fourth Workshop on Teaching NLP and CL

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Introducing Computational Concepts in a Linguistics Olympiad
Patrick Littell | Lori Levin | Jason Eisner | Dragomir Radev
Proceedings of the Fourth Workshop on Teaching NLP and CL

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Random Walk Factoid Annotation for Collective Discourse
Ben King | Rahul Jha | Dragomir Radev | Robert Mankoff
Proceedings of the 51st Annual Meeting of the Association for Computational Linguistics (Volume 2: Short Papers)

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A System for Summarizing Scientific Topics Starting from Keywords
Rahul Jha | Amjad Abu-Jbara | Dragomir Radev
Proceedings of the 51st Annual Meeting of the Association for Computational Linguistics (Volume 2: Short Papers)

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Identifying Opinion Subgroups in Arabic Online Discussions
Amjad Abu-Jbara | Ben King | Mona Diab | Dragomir Radev
Proceedings of the 51st Annual Meeting of the Association for Computational Linguistics (Volume 2: Short Papers)

2012

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Reference Scope Identification in Citing Sentences
Amjad Abu-Jbara | Dragomir Radev
Proceedings of the 2012 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies

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AttitudeMiner: Mining Attitude from Online Discussions
Amjad Abu-Jbara | Ahmed Hassan | Dragomir Radev
Proceedings of the Demonstration Session at the Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies

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Rediscovering ACL Discoveries Through the Lens of ACL Anthology Network Citing Sentences
Dragomir Radev | Amjad Abu-Jbara
Proceedings of the ACL-2012 Special Workshop on Rediscovering 50 Years of Discoveries

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Extracting Signed Social Networks from Text
Ahmed Hassan | Amjad Abu-Jbara | Dragomir Radev
Workshop Proceedings of TextGraphs-7: Graph-based Methods for Natural Language Processing

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Subgroup Detection in Ideological Discussions
Amjad Abu-Jbara | Pradeep Dasigi | Mona Diab | Dragomir Radev
Proceedings of the 50th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)

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Subgroup Detector: A System for Detecting Subgroups in Online Discussions
Amjad Abu-Jbara | Dragomir Radev
Proceedings of the ACL 2012 System Demonstrations

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UMichigan: A Conditional Random Field Model for Resolving the Scope of Negation
Amjad Abu-Jbara | Dragomir Radev
*SEM 2012: The First Joint Conference on Lexical and Computational Semantics – Volume 1: Proceedings of the main conference and the shared task, and Volume 2: Proceedings of the Sixth International Workshop on Semantic Evaluation (SemEval 2012)

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Detecting Subgroups in Online Discussions by Modeling Positive and Negative Relations among Participants
Ahmed Hassan | Amjad Abu-Jbara | Dragomir Radev
Proceedings of the 2012 Joint Conference on Empirical Methods in Natural Language Processing and Computational Natural Language Learning

2011

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Coherent Citation-Based Summarization of Scientific Papers
Amjad Abu-Jbara | Dragomir Radev
Proceedings of the 49th Annual Meeting of the Association for Computational Linguistics: Human Language Technologies

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Learning From Collective Human Behavior to Introduce Diversity in Lexical Choice
Vahed Qazvinian | Dragomir R. Radev
Proceedings of the 49th Annual Meeting of the Association for Computational Linguistics: Human Language Technologies

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Identifying the Semantic Orientation of Foreign Words
Ahmed Hassan | Amjad Abu-Jbara | Rahul Jha | Dragomir Radev
Proceedings of the 49th Annual Meeting of the Association for Computational Linguistics: Human Language Technologies

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Clairlib: A Toolkit for Natural Language Processing, Information Retrieval, and Network Analysis
Amjad Abu-Jbara | Dragomir Radev
Proceedings of the ACL-HLT 2011 System Demonstrations

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Rumor has it: Identifying Misinformation in Microblogs
Vahed Qazvinian | Emily Rosengren | Dragomir R. Radev | Qiaozhu Mei
Proceedings of the 2011 Conference on Empirical Methods in Natural Language Processing

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Simultaneous Similarity Learning and Feature-Weight Learning for Document Clustering
Pradeep Muthukrishnan | Dragomir Radev | Qiaozhu Mei
Proceedings of TextGraphs-6: Graph-based Methods for Natural Language Processing

2010

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Identifying Text Polarity Using Random Walks
Ahmed Hassan | Dragomir R. Radev
Proceedings of the 48th Annual Meeting of the Association for Computational Linguistics

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Identifying Non-Explicit Citing Sentences for Citation-Based Summarization.
Vahed Qazvinian | Dragomir R. Radev
Proceedings of the 48th Annual Meeting of the Association for Computational Linguistics

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What’s with the Attitude? Identifying Sentences with Attitude in Online Discussions
Ahmed Hassan | Vahed Qazvinian | Dragomir Radev
Proceedings of the 2010 Conference on Empirical Methods in Natural Language Processing

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Citation Summarization Through Keyphrase Extraction
Vahed Qazvinian | Dragomir R. Radev | Arzucan Özgür
Proceedings of the 23rd International Conference on Computational Linguistics (Coling 2010)

2009

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Detecting Speculations and their Scopes in Scientific Text
Arzucan Özgür | Dragomir R. Radev
Proceedings of the 2009 Conference on Empirical Methods in Natural Language Processing

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Supervised Classification for Extracting Biomedical Events
Arzucan Özgür | Dragomir Radev
Proceedings of the BioNLP 2009 Workshop Companion Volume for Shared Task

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The ACL Anthology Network Corpus
Dragomir R. Radev | Pradeep Muthukrishnan | Vahed Qazvinian
Proceedings of the 2009 Workshop on Text and Citation Analysis for Scholarly Digital Libraries (NLPIR4DL)

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Using Citations to Generate surveys of Scientific Paradigms
Saif Mohammad | Bonnie Dorr | Melissa Egan | Ahmed Hassan | Pradeep Muthukrishan | Vahed Qazvinian | Dragomir Radev | David Zajic
Proceedings of Human Language Technologies: The 2009 Annual Conference of the North American Chapter of the Association for Computational Linguistics

2008

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The ACL Anthology Reference Corpus: A Reference Dataset for Bibliographic Research in Computational Linguistics
Steven Bird | Robert Dale | Bonnie Dorr | Bryan Gibson | Mark Joseph | Min-Yen Kan | Dongwon Lee | Brett Powley | Dragomir Radev | Yee Fan Tan
Proceedings of the Sixth International Conference on Language Resources and Evaluation (LREC'08)

The ACL Anthology is a digital archive of conference and journal papers in natural language processing and computational linguistics. Its primary purpose is to serve as a reference repository of research results, but we believe that it can also be an object of study and a platform for research in its own right. We describe an enriched and standardized reference corpus derived from the ACL Anthology that can be used for research in scholarly document processing. This corpus, which we call the ACL Anthology Reference Corpus (ACL ARC), brings together the recent activities of a number of research groups around the world. Our goal is to make the corpus widely available, and to encourage other researchers to use it as a standard testbed for experiments in both bibliographic and bibliometric research.

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Modeling Document Dynamics: an Evolutionary Approach
Jahna Otterbacher | Dragomir Radev
Proceedings of the Sixth International Conference on Language Resources and Evaluation (LREC'08)

News articles about the same event published over time have properties that challenge NLP and IR applications. A cluster of such texts typically exhibits instances of paraphrase and contradiction, as sources update the facts surrounding the story, often due to an ongoing investigation. The current hypothesis is that the stories “evolve” over time, beginning with the first text published on a given topic. This is tested using a phylogenetic approach as well as one based on language modeling. The fit of the evolutionary models is evaluated with respect to how well they facilitate the recovery of chronological relationships between the documents. Over all data clusters, the language modeling approach consistently outperforms the phylogenetics model. However, on manually collected clusters in which the documents are published within short time spans of one another, both have a similar performance, and produce statistically significant results on the document chronology recovery evaluation.

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The North American Computational Linguistics Olympiad (NACLO)
Dragomir R. Radev | Lori Levin | Thomas E. Payne
Proceedings of the Third Workshop on Issues in Teaching Computational Linguistics

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Tracking the Dynamic Evolution of Participants Salience in a Discussion
Ahmed Hassan | Anthony Fader | Michael H. Crespin | Kevin M. Quinn | Burt L. Monroe | Michael Colaresi | Dragomir R. Radev
Proceedings of the 22nd International Conference on Computational Linguistics (Coling 2008)

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Detecting Multiple Facets of an Event using Graph-Based Unsupervised Methods
Pradeep Muthukrishnan | Joshua Gerrish | Dragomir R. Radev
Proceedings of the 22nd International Conference on Computational Linguistics (Coling 2008)

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Scientific Paper Summarization Using Citation Summary Networks
Vahed Qazvinian | Dragomir R. Radev
Proceedings of the 22nd International Conference on Computational Linguistics (Coling 2008)

2007

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Semi-Supervised Classification for Extracting Protein Interaction Sentences using Dependency Parsing
Güneş Erkan | Arzucan Özgür | Dragomir R. Radev
Proceedings of the 2007 Joint Conference on Empirical Methods in Natural Language Processing and Computational Natural Language Learning (EMNLP-CoNLL)

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MavenRank: Identifying Influential Members of the US Senate Using Lexical Centrality
Anthony Fader | Dragomir R. Radev | Michael H. Crespin | Burt L. Monroe | Kevin M. Quinn | Michael Colaresi
Proceedings of the 2007 Joint Conference on Empirical Methods in Natural Language Processing and Computational Natural Language Learning (EMNLP-CoNLL)

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Proceedings of the Second Workshop on TextGraphs: Graph-Based Algorithms for Natural Language Processing
Chris Biemann | Irina Matveeva | Rada Mihalcea | Dragomir Radev
Proceedings of the Second Workshop on TextGraphs: Graph-Based Algorithms for Natural Language Processing

2006

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Graph-based Algorithms for Natural Language Processing and Information Retrieval
Rada Mihalcea | Dragomir Radev
Proceedings of the Human Language Technology Conference of the NAACL, Companion Volume: Tutorial Abstracts

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Lexical similarity can distinguish between automatic and manual translations
Agam Patel | Dragomir R. Radev
Proceedings of the Fifth International Conference on Language Resources and Evaluation (LREC’06)

We consider the problem of identifying automatic translations from manual translations of the same sentence. Using two different similarity metrics (BLEU and Levenshtein edit distance), we found out that automatic translations are closer to each other than they are to manual translations. We also use phylogenetic trees to provide a visual representation of the distances between pairs of individual sentences in a set of translations. The differences in lexical distance are statistically significant, both for Chinese to English and for Arabic to English translations.

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Adding Syntax to Dynamic Programming for Aligning Comparable Texts for the Generation of Paraphrases
Siwei Shen | Dragomir R. Radev | Agam Patel | Güneş Erkan
Proceedings of the COLING/ACL 2006 Main Conference Poster Sessions

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LexNet: A Graphical Environment for Graph-Based NLP
Dragomir R. Radev | Güneş Erkan | Anthony Fader | Patrick Jordan | Siwei Shen | James P. Sweeney
Proceedings of the COLING/ACL 2006 Interactive Presentation Sessions

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Proceedings of TextGraphs: the First Workshop on Graph Based Methods for Natural Language Processing
Rada Mihalcea | Dragomir Radev
Proceedings of TextGraphs: the First Workshop on Graph Based Methods for Natural Language Processing

2005

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Proceedings of the Second ACL Workshop on Effective Tools and Methodologies for Teaching NLP and CL
Chris Brew | Dragomir Radev
Proceedings of the Second ACL Workshop on Effective Tools and Methodologies for Teaching NLP and CL

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Using Random Walks for Question-focused Sentence Retrieval
Jahna Otterbacher | Güneş Erkan | Dragomir Radev
Proceedings of Human Language Technology Conference and Conference on Empirical Methods in Natural Language Processing

2004

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RevisionBank: A Resource for Revision-based Multi-document Summarization and Evaluation
Jahna Otterbacher | Dragomir Radev
Proceedings of the Fourth International Conference on Language Resources and Evaluation (LREC’04)

Multi-document summaries produced via sentence extraction often suffer from a number of cohesion problems, including dangling anaphora, sudden shifts in topic and incorrect or awkward chronological ordering. Therefore, the development of an automated revision process to correct such problems is a research area of current interest. We present the RevisionBank, a corpus of 240 extractive, multi-document summaries that have been manually revised to promote cohesion. The summaries were revised by six linguistic students using a constrained set of revision operations that we previously developed. In the current paper, we describe the process of developing a taxonomy of cohesion problems and corrective revision operators that address such problems, as well as an annotation schema for our corpus. Finally, we discuss how our taxonomy and corpus can be used for the study of revision-based multi-document summarization as well as for summary evaluation.

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CST Bank: A Corpus for the Study of Cross-document Structural Relationships
Dragomir Radev | Jahna Otterbacher | Zhu Zhang
Proceedings of the Fourth International Conference on Language Resources and Evaluation (LREC’04)

Clusters of multiple news stories related to the same topic exhibit a number of interesting properties. For example, when documents have been published at various points in time or by different authors or news agencies, one finds many instances of paraphrasing, information overlap and even contradiction. The current paper presents the Cross-document Structure Theory (CST) Bank, a collection of multi-document clusters in which pairs of sentences from different documents have been annotated for cross-document structure theory relationships. We will describe how we built the corpus, including our method for reducing the number of sentence pairs to be annotated by our hired judges, using lexical similarity measures. Finally, we will describe how CST and the CST Bank can be applied to different research areas such as multi-document summarization.

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MEAD - A Platform for Multidocument Multilingual Text Summarization
Dragomir Radev | Timothy Allison | Sasha Blair-Goldensohn | John Blitzer | Arda Çelebi | Stanko Dimitrov | Elliott Drabek | Ali Hakim | Wai Lam | Danyu Liu | Jahna Otterbacher | Hong Qi | Horacio Saggion | Simone Teufel | Michael Topper | Adam Winkel | Zhu Zhang
Proceedings of the Fourth International Conference on Language Resources and Evaluation (LREC’04)

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A Smorgasbord of Features for Statistical Machine Translation
Franz Josef Och | Daniel Gildea | Sanjeev Khudanpur | Anoop Sarkar | Kenji Yamada | Alex Fraser | Shankar Kumar | Libin Shen | David Smith | Katherine Eng | Viren Jain | Zhen Jin | Dragomir Radev
Proceedings of the Human Language Technology Conference of the North American Chapter of the Association for Computational Linguistics: HLT-NAACL 2004

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A Scaleable Multi-document Centroid-based Summarizer
Dragomir Radev | Timothy Allison | Matthew Craig | Stanko Dimitrov | Kareem Omer | Michael Topper | Adam Winkel | Jin Yi
Demonstration Papers at HLT-NAACL 2004

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Computational Linkuistics: Word Triggers across Hyperlinks
Dragomir Radev | Hong Qi | Adam Winkel | Daniel Tam
Proceedings of HLT-NAACL 2004: Short Papers

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Comparing Semantically Related Sentences: The Case of Paraphrase Versus Subsumption
Jahna Otterbacher | Dragomir Radev
COLING 2004: Proceedings of the 20th International Conference on Computational Linguistics

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LexPageRank: Prestige in Multi-Document Text Summarization
Güneş Erkan | Dragomir R. Radev
Proceedings of the 2004 Conference on Empirical Methods in Natural Language Processing

2003

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Sub-event based multi-document summarization
Naomi Daniel | Dragomir Radev | Timothy Allison
Proceedings of the HLT-NAACL 03 Text Summarization Workshop

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Multi-document summarization using off the shelf compression software
Amardeep Grewal | Timothy Allison | Stanko Dimitrov | Dragomir Radev
Proceedings of the HLT-NAACL 03 Text Summarization Workshop

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Evaluation Challenges in Large-Scale Document Summarization
Dragomir R. Radev | Simone Teufel | Horacio Saggion | Wai Lam | John Blitzer | Hong Qi | Arda Çelebi | Danyu Liu | Elliott Drabek
Proceedings of the 41st Annual Meeting of the Association for Computational Linguistics

2002

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Introduction to the Special Issue on Summarization
Dragomir R. Radev | Eduard Hovy | Kathleen McKeown
Computational Linguistics, Volume 28, Number 4, December 2002

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Developing Infrastructure for the Evaluation of Single and Multi-document Summarization Systems in a Cross-lingual Environment
Horacio Saggion | Dragomir Radev | Simone Teufel | Wai Lam | Stephanie M. Strassel
Proceedings of the Third International Conference on Language Resources and Evaluation (LREC’02)

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Evaluating Web-based Question Answering Systems
Dragomir R. Radev | Hong Qi | Harris Wu | Weiguo Fan
Proceedings of the Third International Conference on Language Resources and Evaluation (LREC’02)

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Meta-evaluation of Summaries in a Cross-lingual Environment using Content-based Metrics
Horacio Saggion | Dragomir Radev | Simone Teufel | Wai Lam
COLING 2002: The 19th International Conference on Computational Linguistics

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Revisions that improve cohesion in multi-document summaries: a preliminary study
Jahna C. Otterbacher | Dragomir R. Radev | Airong Luo
Proceedings of the ACL-02 Workshop on Automatic Summarization

2001

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Answering What-Is Questions by Virtual Annotation
John Prager | Dragomir Radev | Krzysztof Czuba
Proceedings of the First International Conference on Human Language Technology Research

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NewsInEssence: A System For Domain-Independent, Real-Time News Clustering and Multi-Document Summarization
Dragomir R. Radev | Sasha Blair-Goldensohn | Zhu Zhang | Revathi Sundara Raghavan
Proceedings of the First International Conference on Human Language Technology Research

2000

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Ranking suspected answers to natural language questions using predictive annotation
Dragomir R. Radev | John Prager | Valerie Samn
Sixth Applied Natural Language Processing Conference

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Centroid-based summarization of multiple documents: sentence extraction, utility-based evaluation, and user studies
Dragomir R. Radev | Hongyan Jing | Malgorzata Budzikowska
NAACL-ANLP 2000 Workshop: Automatic Summarization

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A Common Theory of Information Fusion from Multiple Text Sources Step One: Cross-Document Structure
Dragomir Radev
1st SIGdial Workshop on Discourse and Dialogue

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Automatic summarization of search engine hit lists
Dragomir R. Radev | Weiguo Fan
ACL-2000 Workshop on Recent Advances in Natural Language Processing and Information Retrieval

1998

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Learning Correlations between Linguistic Indicators and Semantic Constraints: Reuse of Context-Dependent Descriptions of Entities
Dragomir R. Radev
36th Annual Meeting of the Association for Computational Linguistics and 17th International Conference on Computational Linguistics, Volume 2

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Learning Correlations between Linguistic Indicators and Semantic Constraints: Reuse of Context-Dependent Descriptions of Entities
Dragomir R. Radev
COLING 1998 Volume 2: The 17th International Conference on Computational Linguistics

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Generating Natural Language Summaries from Multiple On-Line Sources
Dragomir R. Radev | Kathleen R. McKeown
Computational-Linguistics, Volume 24, Number 3, September 1998

1997

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Building a Generation Knowledge Source using Internet-Accessible Newswire
Dragomir R. Radev | Kathleen R. McKeown
Fifth Conference on Applied Natural Language Processing

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Software Re-Use and Evolution in Text Generation Applications
Karen Kukich | Rebecca Passonneau | Kathleen McKeown | Dragomir Radev | Vasileios Hatzivassiloglou | Hongyan Jing
From Research to Commercial Applications: Making NLP Work in Practice

1996

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Using Word Class for Part-of-speech Disambiguation
Evelyne Tzoukermann | Dragomir R. Radev
Fourth Workshop on Very Large Corpora

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An Architecture For Distributed Natural Language Summarization
Dragomir R. Radev
Eighth International Natural Language Generation Workshop (Posters and Demonstrations)

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