Kai Shu


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Proceedings of the Workshop on Combating Online Hostile Posts in Regional Languages during Emergency Situations
Tanmoy Chakraborty | Md. Shad Akhtar | Kai Shu | H. Russell Bernard | Maria Liakata | Preslav Nakov | Shivam Sharma | Chhavi Sharma | Shivani Kumar | Yash Kumar Atri | Sarah Masud | Sunil Saumya | Megha Sundriyal | Karan Goyal | Anam Fatima | Aseem Srivastava
Proceedings of the Workshop on Combating Online Hostile Posts in Regional Languages during Emergency Situations


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Enhancing Model Robustness and Fairness with Causality: A Regularization Approach
Zhao Wang | Kai Shu | Aron Culotta
Proceedings of the First Workshop on Causal Inference and NLP

Recent work has raised concerns on the risk of spurious correlations and unintended biases in statistical machine learning models that threaten model robustness and fairness. In this paper, we propose a simple and intuitive regularization approach to integrate causal knowledge during model training and build a robust and fair model by emphasizing causal features and de-emphasizing spurious features. Specifically, we first manually identify causal and spurious features with principles inspired from the counterfactual framework of causal inference. Then, we propose a regularization approach to penalize causal and spurious features separately. By adjusting the strength of the penalty for each type of feature, we build a predictive model that relies more on causal features and less on non-causal features. We conduct experiments to evaluate model robustness and fairness on three datasets with multiple metrics. Empirical results show that the new models built with causal awareness significantly improve model robustness with respect to counterfactual texts and model fairness with respect to sensitive attributes.


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Authorship Attribution for Neural Text Generation
Adaku Uchendu | Thai Le | Kai Shu | Dongwon Lee
Proceedings of the 2020 Conference on Empirical Methods in Natural Language Processing (EMNLP)

In recent years, the task of generating realistic short and long texts have made tremendous advancements. In particular, several recently proposed neural network-based language models have demonstrated their astonishing capabilities to generate texts that are challenging to distinguish from human-written texts with the naked eye. Despite many benefits and utilities of such neural methods, in some applications, being able to tell the “author” of a text in question becomes critically important. In this work, in the context of this Turing Test, we investigate the so-called authorship attribution problem in three versions: (1) given two texts T1 and T2, are both generated by the same method or not? (2) is the given text T written by a human or machine? (3) given a text T and k candidate neural methods, can we single out the method (among k alternatives) that generated T? Against one humanwritten and eight machine-generated texts (i.e., CTRL, GPT, GPT2, GROVER, XLM, XLNET, PPLM, FAIR), we empirically experiment with the performance of various models in three problems. By and large, we find that most generators still generate texts significantly different from human-written ones, thereby making three problems easier to solve. However, the qualities of texts generated by GPT2, GROVER, and FAIR are better, often confusing machine classifiers in solving three problems. All codes and datasets of our experiments are available at: https://bit.ly/ 302zWdz