Giuseppe Castellucci


2020

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GAN-BERT: Generative Adversarial Learning for Robust Text Classification with a Bunch of Labeled Examples
Danilo Croce | Giuseppe Castellucci | Roberto Basili
Proceedings of the 58th Annual Meeting of the Association for Computational Linguistics

Recent Transformer-based architectures, e.g., BERT, provide impressive results in many Natural Language Processing tasks. However, most of the adopted benchmarks are made of (sometimes hundreds of) thousands of examples. In many real scenarios, obtaining high- quality annotated data is expensive and time consuming; in contrast, unlabeled examples characterizing the target task can be, in general, easily collected. One promising method to enable semi-supervised learning has been proposed in image processing, based on Semi- Supervised Generative Adversarial Networks. In this paper, we propose GAN-BERT that ex- tends the fine-tuning of BERT-like architectures with unlabeled data in a generative adversarial setting. Experimental results show that the requirement for annotated examples can be drastically reduced (up to only 50-100 annotated examples), still obtaining good performances in several sentence classification tasks.

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Proceedings of the First International Workshop on Natural Language Processing Beyond Text
Giuseppe Castellucci | Simone Filice | Soujanya Poria | Erik Cambria | Lucia Specia
Proceedings of the First International Workshop on Natural Language Processing Beyond Text

2017

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Deep Learning in Semantic Kernel Spaces
Danilo Croce | Simone Filice | Giuseppe Castellucci | Roberto Basili
Proceedings of the 55th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)

Kernel methods enable the direct usage of structured representations of textual data during language learning and inference tasks. Expressive kernels, such as Tree Kernels, achieve excellent performance in NLP. On the other side, deep neural networks have been demonstrated effective in automatically learning feature representations during training. However, their input is tensor data, i.e., they can not manage rich structured information. In this paper, we show that expressive kernels and deep neural networks can be combined in a common framework in order to (i) explicitly model structured information and (ii) learn non-linear decision functions. We show that the input layer of a deep architecture can be pre-trained through the application of the Nystrom low-rank approximation of kernel spaces. The resulting “kernelized” neural network achieves state-of-the-art accuracy in three different tasks.

2016

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A Language Independent Method for Generating Large Scale Polarity Lexicons
Giuseppe Castellucci | Danilo Croce | Roberto Basili
Proceedings of the Tenth International Conference on Language Resources and Evaluation (LREC'16)

Sentiment Analysis systems aims at detecting opinions and sentiments that are expressed in texts. Many approaches in literature are based on resources that model the prior polarity of words or multi-word expressions, i.e. a polarity lexicon. Such resources are defined by teams of annotators, i.e. a manual annotation is provided to associate emotional or sentiment facets to the lexicon entries. The development of such lexicons is an expensive and language dependent process, making them often not covering all the linguistic sentiment phenomena. Moreover, once a lexicon is defined it can hardly be adopted in a different language or even a different domain. In this paper, we present several Distributional Polarity Lexicons (DPLs), i.e. large-scale polarity lexicons acquired with an unsupervised methodology based on Distributional Models of Lexical Semantics. Given a set of heuristically annotated sentences from Twitter, we transfer the sentiment information from sentences to words. The approach is mostly unsupervised, and experimental evaluations on Sentiment Analysis tasks in two languages show the benefits of the generated resources. The generated DPLs are publicly available in English and Italian.

2015

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KeLP: a Kernel-based Learning Platform for Natural Language Processing
Simone Filice | Giuseppe Castellucci | Danilo Croce | Roberto Basili
Proceedings of ACL-IJCNLP 2015 System Demonstrations

2014

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UNITOR: Aspect Based Sentiment Analysis with Structured Learning
Giuseppe Castellucci | Simone Filice | Danilo Croce | Roberto Basili
Proceedings of the 8th International Workshop on Semantic Evaluation (SemEval 2014)

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HuRIC: a Human Robot Interaction Corpus
Emanuele Bastianelli | Giuseppe Castellucci | Danilo Croce | Luca Iocchi | Roberto Basili | Daniele Nardi
Proceedings of the Ninth International Conference on Language Resources and Evaluation (LREC'14)

Recent years show the development of large scale resources (e.g. FrameNet for the Frame Semantics) that supported the definition of several state-of-the-art approaches in Natural Language Processing. However, the reuse of existing resources in heterogeneous domains such as Human Robot Interaction is not straightforward. The generalization offered by many data driven methods is strongly biased by the employed data, whose performance in out-of-domain conditions exhibit large drops. In this paper, we present the Human Robot Interaction Corpus (HuRIC). It is made of audio files paired with their transcriptions referring to commands for a robot, e.g. in a home environment. The recorded sentences are annotated with different kinds of linguistic information, ranging from morphological and syntactic information to rich semantic information, according to the Frame Semantics, to characterize robot actions, and Spatial Semantics, to capture the robot environment. All texts are represented through the Abstract Meaning Representation, to adopt a simple but expressive representation of commands, that can be easily translated into the internal representation of the robot.

2013

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Textual Inference and Meaning Representation in Human Robot Interaction
Emanuele Bastianelli | Giuseppe Castellucci | Danilo Croce | Roberto Basili
Proceedings of the Joint Symposium on Semantic Processing. Textual Inference and Structures in Corpora

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UNITOR: Combining Syntactic and Semantic Kernels for Twitter Sentiment Analysis
Giuseppe Castellucci | Simone Filice | Danilo Croce | Roberto Basili
Second Joint Conference on Lexical and Computational Semantics (*SEM), Volume 2: Proceedings of the Seventh International Workshop on Semantic Evaluation (SemEval 2013)