Benjamin Roth


2021

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Knodle: Modular Weakly Supervised Learning with PyTorch
Anastasiia Sedova | Andreas Stephan | Marina Speranskaya | Benjamin Roth
Proceedings of the 6th Workshop on Representation Learning for NLP (RepL4NLP-2021)

Strategies for improving the training and prediction quality of weakly supervised machine learning models vary in how much they are tailored to a specific task or integrated with a specific model architecture. In this work, we introduce Knodle, a software framework that treats weak data annotations, deep learning models, and methods for improving weakly supervised training as separate, modular components. This modularization gives the training process access to fine-grained information such as data set characteristics, matches of heuristic rules, or elements of the deep learning model ultimately used for prediction. Hence, our framework can encompass a wide range of training methods for improving weak supervision, ranging from methods that only look at correlations of rules and output classes (independently of the machine learning model trained with the resulting labels), to those that harness the interplay of neural networks and weakly labeled data. We illustrate the benchmarking potential of the framework with a performance comparison of several reference implementations on a selection of datasets that are already available in Knodle.

2020

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Intent Recognition in Doctor-Patient Interviews
Robin Rojowiec | Benjamin Roth | Maximilian Fink
Proceedings of the 12th Language Resources and Evaluation Conference

Learning to interview patients to find out their disease is an essential part of the training of medical students. The practical part of this training has traditionally relied on paid actors that play the role of a patient to be interviewed. This process is expensive and severely limits the amount of practice per student. In this work, we present a novel data set and methods based on Natural Language Processing, for making progress towards modern applications and e-learning tools that support this training by providing language-based user interfaces with virtual patients. A data set of german transcriptions from live doctor-patient interviews was collected. These transcriptions are based on audio recordings of exercise sessions within the university and only the doctor’s utterances could be transcribed. We annotated each utterance with an intent inventory characterizing the purpose of the question or statement. For some intent classes, the data only contains a few samples, and we apply Information Retrieval and Deep Learning methods that are robust with respect to small amounts of training data for recognizing the intent of an utterance and providing the correct response. Our results show that the models are effective and they provide baseline performance scores on the data set for further research.

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Dirichlet-Smoothed Word Embeddings for Low-Resource Settings
Jakob Jungmaier | Nora Kassner | Benjamin Roth
Proceedings of the 12th Language Resources and Evaluation Conference

Nowadays, classical count-based word embeddings using positive pointwise mutual information (PPMI) weighted co-occurrence matrices have been widely superseded by machine-learning-based methods like word2vec and GloVe. But these methods are usually applied using very large amounts of text data. In many cases, however, there is not much text data available, for example for specific domains or low-resource languages. This paper revisits PPMI by adding Dirichlet smoothing to correct its bias towards rare words. We evaluate on standard word similarity data sets and compare to word2vec and the recent state of the art for low-resource settings: Positive and Unlabeled (PU) Learning for word embeddings. The proposed method outperforms PU-Learning for low-resource settings and obtains competitive results for Maltese and Luxembourgish.

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UniSent: Universal Adaptable Sentiment Lexica for 1000+ Languages
Ehsaneddin Asgari | Fabienne Braune | Benjamin Roth | Christoph Ringlstetter | Mohammad Mofrad
Proceedings of the 12th Language Resources and Evaluation Conference

In this paper, we introduce UniSent universal sentiment lexica for 1000+ languages. Sentiment lexica are vital for sentiment analysis in absence of document-level annotations, a very common scenario for low-resource languages. To the best of our knowledge, UniSent is the largest sentiment resource to date in terms of the number of covered languages, including many low resource ones. In this work, we use a massively parallel Bible corpus to project sentiment information from English to other languages for sentiment analysis on Twitter data. We introduce a method called DomDrift to mitigate the huge domain mismatch between Bible and Twitter by a confidence weighting scheme that uses domain-specific embeddings to compare the nearest neighbors for a candidate sentiment word in the source (Bible) and target (Twitter) domain. We evaluate the quality of UniSent in a subset of languages for which manually created ground truth was available, Macedonian, Czech, German, Spanish, and French. We show that the quality of UniSent is comparable to manually created sentiment resources when it is used as the sentiment seed for the task of word sentiment prediction on top of embedding representations. In addition, we show that emoticon sentiments could be reliably predicted in the Twitter domain using only UniSent and monolingual embeddings in German, Spanish, French, and Italian. With the publication of this paper, we release the UniSent sentiment lexica at http://language-lab.info/unisent.

2019

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Domain adaptation for part-of-speech tagging of noisy user-generated text
Luisa März | Dietrich Trautmann | Benjamin Roth
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)

The performance of a Part-of-speech (POS) tagger is highly dependent on the domain of the processed text, and for many domains there is no or only very little training data available. This work addresses the problem of POS tagging noisy user-generated text using a neural network. We propose an architecture that trains an out-of-domain model on a large newswire corpus, and transfers those weights by using them as a prior for a model trained on the target domain (a data-set of German Tweets) for which there is very little annotations available. The neural network has a standard bidirectional LSTM at its core. However, we find it crucial to also encode a set of task-specific features, and to obtain reliable (source-domain and target-domain) word representations. Experiments with different regularization techniques such as early stopping, dropout and fine-tuning the domain adaptation prior weights are conducted. Our best model uses external weights from the out-of-domain model, as well as feature embeddings, pre-trained word and sub-word embeddings and achieves a tagging accuracy of slightly over 90%, improving on the previous state of the art for this task.

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Proceedings of the Workshop on Extracting Structured Knowledge from Scientific Publications
Vivi Nastase | Benjamin Roth | Laura Dietz | Andrew McCallum
Proceedings of the Workshop on Extracting Structured Knowledge from Scientific Publications

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Interpretable Question Answering on Knowledge Bases and Text
Alona Sydorova | Nina Poerner | Benjamin Roth
Proceedings of the 57th Annual Meeting of the Association for Computational Linguistics

Interpretability of machine learning (ML) models becomes more relevant with their increasing adoption. In this work, we address the interpretability of ML based question answering (QA) models on a combination of knowledge bases (KB) and text documents. We adapt post hoc explanation methods such as LIME and input perturbation (IP) and compare them with the self-explanatory attention mechanism of the model. For this purpose, we propose an automatic evaluation paradigm for explanation methods in the context of QA. We also conduct a study with human annotators to evaluate whether explanations help them identify better QA models. Our results suggest that IP provides better explanations than LIME or attention, according to both automatic and human evaluation. We obtain the same ranking of methods in both experiments, which supports the validity of our automatic evaluation paradigm.

2018

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Joint Bootstrapping Machines for High Confidence Relation Extraction
Pankaj Gupta | Benjamin Roth | Hinrich Schütze
Proceedings of the 2018 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies, Volume 1 (Long Papers)

Semi-supervised bootstrapping techniques for relationship extraction from text iteratively expand a set of initial seed instances. Due to the lack of labeled data, a key challenge in bootstrapping is semantic drift: if a false positive instance is added during an iteration, then all following iterations are contaminated. We introduce BREX, a new bootstrapping method that protects against such contamination by highly effective confidence assessment. This is achieved by using entity and template seeds jointly (as opposed to just one as in previous work), by expanding entities and templates in parallel and in a mutually constraining fashion in each iteration and by introducing higherquality similarity measures for templates. Experimental results show that BREX achieves an F1 that is 0.13 (0.87 vs. 0.74) better than the state of the art for four relationships.

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Evaluating neural network explanation methods using hybrid documents and morphosyntactic agreement
Nina Poerner | Hinrich Schütze | Benjamin Roth
Proceedings of the 56th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)

The behavior of deep neural networks (DNNs) is hard to understand. This makes it necessary to explore post hoc explanation methods. We conduct the first comprehensive evaluation of explanation methods for NLP. To this end, we design two novel evaluation paradigms that cover two important classes of NLP problems: small context and large context problems. Both paradigms require no manual annotation and are therefore broadly applicable. We also introduce LIMSSE, an explanation method inspired by LIME that is designed for NLP. We show empirically that LIMSSE, LRP and DeepLIFT are the most effective explanation methods and recommend them for explaining DNNs in NLP.

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Interpretable Textual Neuron Representations for NLP
Nina Poerner | Benjamin Roth | Hinrich Schütze
Proceedings of the 2018 EMNLP Workshop BlackboxNLP: Analyzing and Interpreting Neural Networks for NLP

Input optimization methods, such as Google Deep Dream, create interpretable representations of neurons for computer vision DNNs. We propose and evaluate ways of transferring this technology to NLP. Our results suggest that gradient ascent with a gumbel softmax layer produces n-gram representations that outperform naive corpus search in terms of target neuron activation. The representations highlight differences in syntax awareness between the language and visual models of the Imaginet architecture.

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Joint Aspect and Polarity Classification for Aspect-based Sentiment Analysis with End-to-End Neural Networks
Martin Schmitt | Simon Steinheber | Konrad Schreiber | Benjamin Roth
Proceedings of the 2018 Conference on Empirical Methods in Natural Language Processing

In this work, we propose a new model for aspect-based sentiment analysis. In contrast to previous approaches, we jointly model the detection of aspects and the classification of their polarity in an end-to-end trainable neural network. We conduct experiments with different neural architectures and word representations on the recent GermEval 2017 dataset. We were able to show considerable performance gains by using the joint modeling approach in all settings compared to pipeline approaches. The combination of a convolutional neural network and fasttext embeddings outperformed the best submission of the shared task in 2017, establishing a new state of the art.

2017

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Towards Bootstrapping a Polarity Shifter Lexicon using Linguistic Features
Marc Schulder | Michael Wiegand | Josef Ruppenhofer | Benjamin Roth
Proceedings of the Eighth International Joint Conference on Natural Language Processing (Volume 1: Long Papers)

We present a major step towards the creation of the first high-coverage lexicon of polarity shifters. In this work, we bootstrap a lexicon of verbs by exploiting various linguistic features. Polarity shifters, such as “abandon”, are similar to negations (e.g. “not”) in that they move the polarity of a phrase towards its inverse, as in “abandon all hope”. While there exist lists of negation words, creating comprehensive lists of polarity shifters is far more challenging due to their sheer number. On a sample of manually annotated verbs we examine a variety of linguistic features for this task. Then we build a supervised classifier to increase coverage. We show that this approach drastically reduces the annotation effort while ensuring a high-precision lexicon. We also show that our acquired knowledge of verbal polarity shifters improves phrase-level sentiment analysis.

2016

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Comparing Convolutional Neural Networks to Traditional Models for Slot Filling
Heike Adel | Benjamin Roth | Hinrich Schütze
Proceedings of the 2016 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies

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Multilingual Relation Extraction using Compositional Universal Schema
Patrick Verga | David Belanger | Emma Strubell | Benjamin Roth | Andrew McCallum
Proceedings of the 2016 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies

2015

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Compositional Vector Space Models for Knowledge Base Completion
Arvind Neelakantan | Benjamin Roth | Andrew McCallum
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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Automatic Food Categorization from Large Unlabeled Corpora and Its Impact on Relation Extraction
Michael Wiegand | Benjamin Roth | Dietrich Klakow
Proceedings of the 14th Conference of the European Chapter of the Association for Computational Linguistics

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RelationFactory: A Fast, Modular and Effective System for Knowledge Base Population
Benjamin Roth | Tassilo Barth | Grzegorz Chrupała | Martin Gropp | Dietrich Klakow
Proceedings of the Demonstrations at the 14th Conference of the European Chapter of the Association for Computational Linguistics

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Unsupervised Parsing for Generating Surface-Based Relation Extraction Patterns
Jens Illig | Benjamin Roth | Dietrich Klakow
Proceedings of the 14th Conference of the European Chapter of the Association for Computational Linguistics, volume 2: Short Papers

2013

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Combining Generative and Discriminative Model Scores for Distant Supervision
Benjamin Roth | Dietrich Klakow
Proceedings of the 2013 Conference on Empirical Methods in Natural Language Processing

2012

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A Gold Standard for Relation Extraction in the Food Domain
Michael Wiegand | Benjamin Roth | Eva Lasarcyk | Stephanie Köser | Dietrich Klakow
Proceedings of the Eighth International Conference on Language Resources and Evaluation (LREC'12)

We present a gold standard for semantic relation extraction in the food domain for German. The relation types that we address are motivated by scenarios for which IT applications present a commercial potential, such as virtual customer advice in which a virtual agent assists a customer in a supermarket in finding those products that satisfy their needs best. Moreover, we focus on those relation types that can be extracted from natural language text corpora, ideally content from the internet, such as web forums, that are easy to retrieve. A typical relation type that meets these requirements are pairs of food items that are usually consumed together. Such a relation type could be used by a virtual agent to suggest additional products available in a shop that would potentially complement the items a customer has already in their shopping cart. Our gold standard comprises structural data, i.e. relation tables, which encode relation instances. These tables are vital in order to evaluate natural language processing systems that extract those relations.

2010

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A survey on the role of negation in sentiment analysis
Michael Wiegand | Alexandra Balahur | Benjamin Roth | Dietrich Klakow | Andrés Montoyo
Proceedings of the Workshop on Negation and Speculation in Natural Language Processing

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Topic Models for Word Sense Disambiguation and Token-Based Idiom Detection
Linlin Li | Benjamin Roth | Caroline Sporleder
Proceedings of the 48th Annual Meeting of the Association for Computational Linguistics

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Machine Translation Using Overlapping Alignments and SampleRank
Benjamin Roth | Andrew McCallum | Marc Dymetman | Nicola Cancedda
Proceedings of the 9th Conference of the Association for Machine Translation in the Americas: Research Papers

We present a conditional-random-field approach to discriminatively-trained phrase-based machine translation in which training and decoding are both cast in a sampling framework and are implemented uniformly in a new probabilistic programming language for factor graphs. In traditional phrase-based translation, decoding infers both a "Viterbi" alignment and the target sentence. In contrast, in our approach, a rich overlapping-phrase alignment is produced by a fast deterministic method, while probabilistic decoding infers only the target sentence, which is then able to leverage arbitrary features of the entire source sentence, target sentence and alignment. By using SampleRank for learning we could in principle efficiently estimate hundreds of thousands of parameters. Test-time decoding is done by MCMC sampling with annealing. To demonstrate the potential of our approach we show preliminary experiments leveraging alignments that may contain overlapping bi-phrases.