GenAI4ELab/papercli-papers huggingface dataset:
User Simulator Assisted Open-ended Conversational Recommendation System
Authors: Qiusi Zhan; Xiaojie Guo; Heng Ji; Lingfei Wu
Venue: ACL 2023 (Proceedings of the 5th Workshop on NLP for Conversational AI (NLP4ConvAI 2023))

Abstract: Conversational recommendation systems (CRS) have gained popularity in e-commerce as they can recommend items during user interactions. However, current open-ended CRS have limited recommendation performance due to their short-sighted training process, which only predicts one utterance at a time without considering its future impact. To address this, we propose a User Simulator (US) that communicates with the CRS using natural language based on given user preferences, enabling long-term reinforcement learning. We also introduce a framework that uses reinforcement learning (RL) with two novel rewards, i.e., recommendation and conversation rewards, to train the CRS. This approach considers the long-term goals and improves both the conversation and recommendation performance of the CRS. Our experiments show that our proposed framework improves the recall of recommendations by almost 100%. Moreover, human evaluation demonstrates the superiority of our framework in enhancing the informativeness of generated utterances.
Evaluating Inter-Bilingual Semantic Parsing for Indian Languages
Authors: Divyanshu Aggarwal; Vivek Gupta; Anoop Kunchukuttan
Venue: ACL 2023 (Proceedings of the 5th Workshop on NLP for Conversational AI (NLP4ConvAI 2023))

Abstract: Despite significant progress in Natural Language Generation for Indian languages (IndicNLP), there is a lack of datasets around complex structured tasks such as semantic parsing. One reason for this imminent gap is the complexity of the logical form, which makes English to multilingual translation difficult. The process involves alignment of logical forms, intents and slots with translated unstructured utterance. To address this, we propose an Inter-bilingual Seq2seq Semantic parsing dataset IE-SemParse Suite for 11 distinct Indian languages. We highlight the proposed task’s practicality, and evaluate existing multilingual seq2seq models across several train-test strategies. Our experiment reveals a high correlation across performance of original multilingual semantic parsing datasets (such as mTOP, multilingual TOP and multiATIS++) and our proposed IE-SemParse suite.
Zero-Shot Dialogue Relation Extraction by Relating Explainable Triggers and Relation Names
Authors: Ze-Song Xu; Yun-Nung Chen
Venue: ACL 2023 (Proceedings of the 5th Workshop on NLP for Conversational AI (NLP4ConvAI 2023))

Abstract: Developing dialogue relation extraction (DRE) systems often requires a large amount of labeled data, which can be costly and time-consuming to annotate. In order to improve scalability and support diverse, unseen relation extraction, this paper proposes a method for leveraging the ability to capture triggers and relate them to previously unseen relation names. Specifically, we introduce a model that enables zero-shot dialogue relation extraction by utilizing trigger-capturing capabilities. Our experiments on a benchmark DialogRE dataset demonstrate that the proposed model achieves significant improvements for both seen and unseen relations. Notably, this is the first attempt at zero-shot dialogue relation extraction using trigger-capturing capabilities, and our results suggest that this approach is effective for inferring previously unseen relation types. Overall, our findings highlight the potential for this method to enhance the scalability and practicality of DRE systems.
Generating Video Game Scripts with Style
Authors: Gaetan Lopez Latouche; Laurence Marcotte; Ben Swanson
Venue: ACL 2023 (Proceedings of the 5th Workshop on NLP for Conversational AI (NLP4ConvAI 2023))

Abstract: While modern language models can generate a scripted scene in the format of a play, movie, or video game cutscene the quality of machine generated text remains behind that of human authors. In this work, we focus on one aspect of this quality gap; generating text in the style of an arbitrary and unseen character. We propose the Style Adaptive Semiparametric Scriptwriter (SASS) which leverages an adaptive weighted style memory to generate dialog lines in accordance with a character’s speaking patterns. Using the LIGHT dataset as well as a new corpus of scripts from twenty-three AAA video games, we show that SASS not only outperforms similar models but in some cases can also be used in conjunction with them to yield further improvement.
A Survey of Challenges and Methods in the Computational Modeling of Multi-Party Dialog
Authors: Ananya Ganesh; Martha Palmer; Katharina Kann
Venue: ACL 2023 (Proceedings of the 5th Workshop on NLP for Conversational AI (NLP4ConvAI 2023))

Abstract: Advances in conversational AI systems, powered in particular by large language models, have facilitated rapid progress in understanding and generating dialog. Typically, task-oriented or open-domain dialog systems have been designed to work with two-party dialog, i.e., the exchange of utterances between a single user and a dialog system. However, modern dialog systems may be deployed in scenarios such as classrooms or meetings where conversational analysis of multiple speakers is required. This survey will present research around computational modeling of “multi-party dialog”, outlining differences from two-party dialog, challenges and issues in working with multi-party dialog, and methods for representing multi-party dialog. We also provide an overview of dialog datasets created for the study of multi-party dialog, as well as tasks that are of interest in this domain.
Conversational Recommendation as Retrieval: A Simple, Strong Baseline
Authors: Raghav Gupta; Renat Aksitov; Samrat Phatale; Simral Chaudhary; Harrison Lee; Abhinav Rastogi
Venue: ACL 2023 (Proceedings of the 5th Workshop on NLP for Conversational AI (NLP4ConvAI 2023))

Abstract: Conversational recommendation systems (CRS) aim to recommend suitable items to users through natural language conversation. However, most CRS approaches do not effectively utilize the signal provided by these conversations. They rely heavily on explicit external knowledge e.g., knowledge graphs to augment the models’ understanding of the items and attributes, which is quite hard to scale. To alleviate this, we propose an alternative information retrieval (IR)-styled approach to the CRS item recommendation task, where we represent conversations as queries and items as documents to be retrieved. We expand the document representation used for retrieval with conversations from the training set. With a simple BM25-based retriever, we show that our task formulation compares favorably with much more complex baselines using complex external knowledge on a popular CRS benchmark. We demonstrate further improvements using user-centric modeling and data augmentation to counter the cold start problem for CRSs.
Adversarial Clean Label Backdoor Attacks and Defenses on Text Classification Systems
Authors: Ashim Gupta; Amrith Krishna
Venue: ACL 2023 (Proceedings of the 8th Workshop on Representation Learning for NLP (RepL4NLP 2023))

Abstract: Clean-label (CL) attack is a form of data poisoning attack where an adversary modifies only the textual input of the training data, without requiring access to the labeling function. CL attacks are relatively unexplored in NLP, as compared to label flipping (LF) attacks, where the latter additionally requires access to the labeling function as well. While CL attacks are more resilient to data sanitization and manual relabeling methods than LF attacks, they often demand as high as ten times the poisoning budget than LF attacks. In this work, we first introduce an Adversarial Clean Label attack which can adversarially perturb in-class training examples for poisoning the training set. We then show that an adversary can significantly bring down the data requirements for a CL attack, using the aforementioned approach, to as low as 20 % of the data otherwise required. We then systematically benchmark and analyze a number of defense methods, for both LF and CL attacks, some previously employed solely for LF attacks in the textual domain and others adapted from computer vision. We find that text-specific defenses greatly vary in their effectiveness depending on their properties.
Do not Mask Randomly: Effective Domain-adaptive Pre-training by Masking In-domain Keywords
Authors: Shahriar Golchin; Mihai Surdeanu; Nazgol Tavabi; Ata Kiapour
Venue: ACL 2023 (Proceedings of the 8th Workshop on Representation Learning for NLP (RepL4NLP 2023))

Abstract: We propose a novel task-agnostic in-domain pre-training method that sits between generic pre-training and fine-tuning. Our approach selectively masks in-domain keywords, i.e., words that provide a compact representation of the target domain. We identify such keywords using KeyBERT (Grootendorst, 2020). We evaluate our approach using six different settings: three datasets combined with two distinct pre-trained language models (PLMs). Our results reveal that the fine-tuned PLMs adapted using our in-domain pre-training strategy outperform PLMs that used in-domain pre-training with random masking as well as those that followed the common pre-train-then-fine-tune paradigm. Further, the overhead of identifying in-domain keywords is reasonable, e.g., 7-15% of the pre-training time (for two epochs) for BERT Large (Devlin et al., 2019).
Grammatical information in BERT sentence embeddings as two-dimensional arrays
Authors: Vivi Nastase; Paola Merlo
Venue: ACL 2023 (Proceedings of the 8th Workshop on Representation Learning for NLP (RepL4NLP 2023))

Abstract: Sentence embeddings induced with various transformer architectures encode much semantic and syntactic information in a distributed manner in a one-dimensional array. We investigate whether specific grammatical information can be accessed in these distributed representations. Using data from a task developed to test rule-like generalizations, our experiments on detecting subject-verb agreement yield several promising results. First, we show that while the usual sentence representations encoded as one-dimensional arrays do not easily support extraction of rule-like regularities, a two-dimensional reshaping of these vectors allows various learning architectures to access such information. Next, we show that various architectures can detect patterns in these two-dimensional reshaped sentence embeddings and successfully learn a model based on smaller amounts of simpler training data, which performs well on more complex test data. This indicates that current sentence embeddings contain information that is regularly distributed, and which can be captured when the embeddings are reshaped into higher dimensional arrays. Our results cast light on representations produced by language models and help move towards developing few-shot learning approaches.
A Multilingual Evaluation of NER Robustness to Adversarial Inputs
Authors: Akshay Srinivasan; Sowmya Vajjala
Venue: ACL 2023 (Proceedings of the 8th Workshop on Representation Learning for NLP (RepL4NLP 2023))

Abstract: Adversarial evaluations of language models typically focus on English alone. In this paper, we performed a multilingual evaluation of Named Entity Recognition (NER) in terms of its robustness to small perturbations in the input. Our results showed the NER models we explored across three languages (English, German and Hindi) are not very robust to such changes, as indicated by the fluctuations in the overall F1 score as well as in a more fine-grained evaluation. With that knowledge, we further explored whether it is possible to improve the existing NER models using a part of the generated adversarial data sets as augmented training data to train a new NER model or as fine-tuning data to adapt an existing NER model. Our results showed that both these approaches improve performance on the original as well as adversarial test sets. While there is no significant difference between the two approaches for English, re-training is significantly better than fine-tuning for German and Hindi.
Retrieval-Augmented Domain Adaptation of Language Models
Authors: Benfeng Xu; Chunxu Zhao; Wenbin Jiang; PengFei Zhu; Songtai Dai; Chao Pang; Zhuo Sun; Shuohuan Wang; Yu Sun
Venue: ACL 2023 (Proceedings of the 8th Workshop on Representation Learning for NLP (RepL4NLP 2023))

Abstract: Language models pretrained on general domain corpora usually exhibit considerable degradation when generalizing to downstream tasks of specialized domains. Existing approaches try to construct PLMs for each specific domains either from scratch or through further pretraining, which not only costs substantial resources, but also fails to cover all target domains at various granularity. In this work, we propose RADA, a novel Retrieval-Augmented framework for Domain Adaptation. We first construct a textual corpora that covers the downstream task at flexible domain granularity and resource availability. We employ it as a pluggable datastore to retrieve informative background knowledge, and integrate them into the standard language model framework to augment representations. We then propose a two-level selection scheme to integrate the most relevant information while alleviating irrelevant noises. Specifically, we introduce a differentiable sampling module as well as an attention mechanism to achieve both passage-level and word-level selection. Such a retrieval-augmented framework enables domain adaptation of language models with flexible domain coverage and fine-grained domain knowledge integration. We conduct comprehensive experiments across biomedical, science and legal domains to demonstrate the effectiveness of the overall framework, and its advantage over existing solutions.
Fine-grained Text Style Transfer with Diffusion-Based Language Models
Authors: Yiwei Lyu; Tiange Luo; Jiacheng Shi; Todd Hollon; Honglak Lee
Venue: ACL 2023 (Proceedings of the 8th Workshop on Representation Learning for NLP (RepL4NLP 2023))

Abstract: Diffusion probabilistic models have shown great success in generating high-quality images controllably, and researchers have tried to utilize this controllability into text generation domain. Previous works on diffusion-based language models have shown that they can be trained without external knowledge (such as pre-trained weights) and still achieve stable performance and controllability. In this paper, we trained a diffusion-based model on StylePTB dataset, the standard benchmark for fine-grained text style transfers. The tasks in StylePTB requires much more refined control over the output text compared to tasks evaluated in previous works, and our model was able to achieve state-of-the-art performance on StylePTB on both individual and compositional transfers. Moreover, our model, trained on limited data from StylePTB without external knowledge, outperforms previous works that utilized pretrained weights, embeddings, and external grammar parsers, and this may indicate that diffusion-based language models have great potential under low-resource settings.
Enhancing text comprehension for Question Answering with Contrastive Learning
Authors: Seungyeon Lee; Minho Lee
Venue: ACL 2023 (Proceedings of the 8th Workshop on Representation Learning for NLP (RepL4NLP 2023))

Abstract: Although Question Answering (QA) have advanced to the human-level language skills in NLP tasks, there is still a problem: the QA model gets confused when there are similar sentences or paragraphs. Existing studies focus on enhancing the text understanding of the candidate answers to improve the overall performance of the QA models. However, since these methods focus on re-ranking queries or candidate answers, they fail to resolve the confusion when many generated answers are similar to the expected answer. To address these issues, we propose a novel contrastive learning framework called ContrastiveQA that alleviates the confusion problem in answer extraction. We propose a supervised method where we generate positive and negative samples from the candidate answers and the given answer, respectively. We thus introduce ContrastiveQA, which uses contrastive learning with sampling data to reduce incorrect answers. Experimental results on four QA benchmarks show the effectiveness of the proposed method.
Towards Flow Graph Prediction of Open-Domain Procedural Texts
Authors: Keisuke Shirai; Hirotaka Kameko; Shinsuke Mori
Venue: ACL 2023 (Proceedings of the 8th Workshop on Representation Learning for NLP (RepL4NLP 2023))

Abstract: Machine comprehension of procedural texts is essential for reasoning about the steps and automating the procedures. However, this requires identifying entities within a text and resolving the relationships between the entities. Previous work focused on the cooking domain and proposed a framework to convert a recipe text into a flow graph (FG) representation. In this work, we propose a framework based on the recipe FG for flow graph prediction of open-domain procedural texts. To investigate flow graph prediction performance in non-cooking domains, we introduce the wikiHow-FG corpus from articles on wikiHow, a website of how-to instruction articles. In experiments, we consider using the existing recipe corpus and performing domain adaptation from the cooking to the target domain. Experimental results show that the domain adaptation models achieve higher performance than those trained only on the cooking or target domain data.
One does not fit all! On the Complementarity of Vision Encoders for Vision and Language Tasks
Authors: Gregor Geigle; Chen Cecilia Liu; Jonas Pfeiffer; Iryna Gurevych
Venue: ACL 2023 (Proceedings of the 8th Workshop on Representation Learning for NLP (RepL4NLP 2023))

Abstract: Current multimodal models, aimed at solving Vision and Language (V+L) tasks, predominantly repurpose Vision Encoders (VE) as feature extractors. While many VEs—of different architectures, trained on different data and objectives—are publicly available, they are not designed for the downstream V+L tasks. Nonetheless, most current work assumes that a single pre-trained VE can serve as a general-purpose encoder. In this work, we focus on analysis and aim to understand whether the information stored within different VEs is complementary, i.e. if providing the model with features from multiple VEs can improve the performance on a target task, and how they are combined. We exhaustively experiment with three popular VEs on six downstream V+L tasks and analyze the attention and VE-dropout patterns. Our analyses suggest that diverse VEs complement each other, resulting in improved downstream V+L task performance, where the improvements are not due to simple ensemble effects (i.e. the performance does not always improve when increasing the number of encoders). We demonstrate that future VEs, which are not repurposed, but explicitly designed for V+L tasks, have the potential of improving performance on the target V+L tasks.
SPC: Soft Prompt Construction for Cross Domain Generalization
Authors: Wenbo Zhao; Arpit Gupta; Tagyoung Chung; Jing Huang
Venue: ACL 2023 (Proceedings of the 8th Workshop on Representation Learning for NLP (RepL4NLP 2023))

Abstract: Recent advances in prompt tuning have proven effective as a new language modeling paradigm for various natural language understanding tasks. However, it is challenging to adapt the soft prompt embeddings to different domains or generalize to low-data settings when learning soft prompts itself is unstable, task-specific, and bias-prone. This paper proposes a principled learning framework—soft prompt construction (SPC)—to facilitate learning domain-adaptable soft prompts. Derived from the SPC framework is a simple loss that can plug into various models and tuning approaches to improve their cross-domain performance. We show SPC can improve upon SOTA for contextual query rewriting, summarization, and paraphrase detection by up to 5%, 19%, and 16%, respectively.
Friendly Neighbors: Contextualized Sequence-to-Sequence Link Prediction
Authors: Adrian Kochsiek; Apoorv Saxena; Inderjeet Nair; Rainer Gemulla
Venue: ACL 2023 (Proceedings of the 8th Workshop on Representation Learning for NLP (RepL4NLP 2023))

Abstract: We propose KGT5-context, a simple sequence-to-sequence model for link prediction (LP) in knowledge graphs (KG). Our work expands on KGT5, a recent LP model that exploits textual features of the KG, has small model size, and is scalable. To reach good predictive performance, however, KGT5 relies on an ensemble with a knowledge graph embedding model, which itself is excessively large and costly to use. In this short paper, we show empirically that adding contextual information — i.e., information about the direct neighborhood of the query entity — alleviates the need for a separate KGE model to obtain good performance. The resulting KGT5-context model is simple, reduces model size significantly, and obtains state-of-the-art performance in our experimental study.
Extracting Multi-valued Relations from Language Models
Authors: Sneha Singhania; Simon Razniewski; Gerhard Weikum
Venue: ACL 2023 (Proceedings of the 8th Workshop on Representation Learning for NLP (RepL4NLP 2023))

Abstract: The widespread usage of latent language representations via pre-trained language models (LMs) suggests that they are a promising source of structured knowledge. However, existing methods focus only on a single object per subject-relation pair, even though often multiple objects are correct. To overcome this limitation, we analyze these representations for their potential to yield materialized multi-object relational knowledge. We formulate the problem as a rank-then-select task. For ranking candidate objects, we evaluate existing prompting techniques and propose new ones incorporating domain knowledge. Among the selection methods, we find that choosing objects with a likelihood above a learned relation-specific threshold gives a 49.5% F1 score. Our results highlight the difficulty of employing LMs for the multi-valued slot-filling task, and pave the way for further research on extracting relational knowledge from latent language representations.
Hierarchical Multi-Instance Multi-Label Learning for Detecting Propaganda Techniques
Authors: Anni Chen; Bhuwan Dhingra
Venue: ACL 2023 (Proceedings of the 8th Workshop on Representation Learning for NLP (RepL4NLP 2023))

Abstract: Since the introduction of the SemEval 2020 Task 11 (CITATION), several approaches have been proposed in the literature for classifying propagandabased on the rhetorical techniques used to influence readers. These methods, however, classify one span at a time, ignoring dependencies from the labels of other spans within the same context. In this paper, we approach propaganda technique classification as aMulti-Instance Multi-Label (MIML) learning problem (CITATION) and propose a simple RoBERTa-based model (CITATION) for classifying all spans in an article simultaneously. Further, we note that, due to the annotation process whereannotators classified the spans by following a decision tree,there is an inherent hierarchical relationship among the differenttechniques, which existing approaches ignore. We incorporate these hierarchical label dependencies by adding an auxiliary classifier for each node in the decision tree to the training objective and ensembling the predictions from the original and auxiliary classifiers at test time. Overall, our model leads to an absolute improvement of 2.47% micro-F1 over the model from the shared task winning team in a cross-validation setup and is the best performing non-ensemble model on the shared task leaderboard.