Junda Wu


2025

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From Selection to Generation: A Survey of LLM-based Active Learning
Yu Xia | Subhojyoti Mukherjee | Zhouhang Xie | Junda Wu | Xintong Li | Ryan Aponte | Hanjia Lyu | Joe Barrow | Hongjie Chen | Franck Dernoncourt | Branislav Kveton | Tong Yu | Ruiyi Zhang | Jiuxiang Gu | Nesreen K. Ahmed | Yu Wang | Xiang Chen | Hanieh Deilamsalehy | Sungchul Kim | Zhengmian Hu | Yue Zhao | Nedim Lipka | Seunghyun Yoon | Ting-Hao Kenneth Huang | Zichao Wang | Puneet Mathur | Soumyabrata Pal | Koyel Mukherjee | Zhehao Zhang | Namyong Park | Thien Huu Nguyen | Jiebo Luo | Ryan A. Rossi | Julian McAuley
Proceedings of the 63rd Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)

Active Learning (AL) has been a powerful paradigm for improving model efficiency and performance by selecting the most informative data points for labeling and training. In recent active learning frameworks, Large Language Models (LLMs) have been employed not only for selection but also for generating entirely new data instances and providing more cost-effective annotations. Motivated by the increasing importance of high-quality data and efficient model training in the era of LLMs, we present a comprehensive survey on LLM-based Active Learning. We introduce an intuitive taxonomy that categorizes these techniques and discuss the transformative roles LLMs can play in the active learning loop. We further examine the impact of AL on LLM learning paradigms and its applications across various domains. Finally, we identify open challenges and propose future research directions. This survey aims to serve as an up-to-date resource for researchers and practitioners seeking to gain an intuitive understanding of LLM-based AL techniques and deploy them to new applications.

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Doc-React: Multi-page Heterogeneous Document Question-answering
Junda Wu | Yu Xia | Tong Yu | Xiang Chen | Sai Sree Harsha | Akash V Maharaj | Ruiyi Zhang | Victor Bursztyn | Sungchul Kim | Ryan A. Rossi | Julian McAuley | Yunyao Li | Ritwik Sinha
Proceedings of the 63rd Annual Meeting of the Association for Computational Linguistics (Volume 2: Short Papers)

Answering questions over multi-page, multimodal documents, including text and figures, is a critical challenge for applications that require answers to integrate information across multiple modalities and contextual dependencies. Existing methods, such as single-turn retrieval-augmented generation (RAG), struggle to retrieve fine-grained and contextually relevant information from large, heterogeneous documents, leading to suboptimal performance. Inspired by iterative frameworks like ReAct, which refine retrieval through feedback, we propose Doc-React, an adaptive iterative framework that balances information gain and uncertainty reduction at each step. Doc-React leverages InfoNCE-guided retrieval to approximate mutual information, enabling dynamic sub-query generation and refinement. A large language model (LLM) serves as both a judge and generator, providing structured feedback to iteratively improve retrieval. By combining mutual information optimization with entropy-aware selection, Doc-React systematically captures relevant multimodal content, achieving strong performance on complex QA tasks

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Large Language Models and Causal Inference in Collaboration: A Comprehensive Survey
Xiaoyu Liu | Paiheng Xu | Junda Wu | Jiaxin Yuan | Yifan Yang | Yuhang Zhou | Fuxiao Liu | Tianrui Guan | Haoliang Wang | Tong Yu | Julian McAuley | Wei Ai | Furong Huang
Findings of the Association for Computational Linguistics: NAACL 2025

Causal inference has demonstrated significant potential to enhance Natural Language Processing (NLP) models in areas such as predictive accuracy, fairness, robustness, and explainability by capturing causal relationships among variables. The rise of generative Large Language Models (LLMs) has greatly impacted various language processing tasks. This survey focuses on research that evaluates or improves LLMs from a causal view in the following areas: reasoning capacity, fairness and safety issues, explainability, and handling multimodality. Meanwhile, LLMs can assist in causal inference tasks, such as causal relationship discovery and causal effect estimation, by leveraging their generation ability and knowledge learned during pre-training. This review explores the interplay between causal inference frameworks and LLMs from both perspectives, emphasizing their collective potential to further the development of more advanced and robust artificial intelligence systems.

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GUI Agents: A Survey
Dang Nguyen | Jian Chen | Yu Wang | Gang Wu | Namyong Park | Zhengmian Hu | Hanjia Lyu | Junda Wu | Ryan Aponte | Yu Xia | Xintong Li | Jing Shi | Hongjie Chen | Viet Dac Lai | Zhouhang Xie | Sungchul Kim | Ruiyi Zhang | Tong Yu | Mehrab Tanjim | Nesreen K. Ahmed | Puneet Mathur | Seunghyun Yoon | Lina Yao | Branislav Kveton | Jihyung Kil | Thien Huu Nguyen | Trung Bui | Tianyi Zhou | Ryan A. Rossi | Franck Dernoncourt
Findings of the Association for Computational Linguistics: ACL 2025

Graphical User Interface (GUI) agents, powered by Large Foundation Models, have emerged as a transformative approach to automating human-computer interaction. These agents autonomously interact with digital systems via GUIs, emulating human actions such as clicking, typing, and navigating visual elements across diverse platforms. Motivated by the growing interest and fundamental importance of GUI agents, we provide a comprehensive survey that categorizes their benchmarks, evaluation metrics, architectures, and training methods. We propose a unified framework that delineates their perception, reasoning, planning, and acting capabilities. Furthermore, we identify important open challenges and discuss key future directions. Finally, this work serves as a basis for practitioners and researchers to gain an intuitive understanding of current progress, techniques, benchmarks, and critical open problems that remain to be addressed.

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Knowledge-Aware Query Expansion with Large Language Models for Textual and Relational Retrieval
Yu Xia | Junda Wu | Sungchul Kim | Tong Yu | Ryan A. Rossi | Haoliang Wang | Julian McAuley
Proceedings of the 2025 Conference of the Nations of the Americas Chapter of the Association for Computational Linguistics: Human Language Technologies (Volume 1: Long Papers)

Large language models (LLMs) have been used to generate query expansions augmenting original queries for improving information search. Recent studies also explore providing LLMs with initial retrieval results to generate query expansions more grounded to document corpus. However, these methods mostly focus on enhancing textual similarities between search queries and target documents, overlooking document relations. For queries like “Find me a highly rated camera for wildlife photography compatible with my Nikon F-Mount lenses”, existing methods may generate expansions that are semantically similar but structurally unrelated to user intents. To handle such semi-structured queries with both textual and relational requirements, in this paper we propose a knowledge-aware query expansion framework, augmenting LLMs with structured document relations from knowledge graph (KG). To further address the limitation of entity-based scoring in existing KG-based methods, we leverage document texts as rich KG node representations and use document-based relation filtering for our Knowledge-Aware Retrieval (KAR). Extensive experiments on three datasets of diverse domains show the advantages of our method compared against state-of-the-art baselines on textual and relational semi-structured retrieval.

2024

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DeCoT: Debiasing Chain-of-Thought for Knowledge-Intensive Tasks in Large Language Models via Causal Intervention
Junda Wu | Tong Yu | Xiang Chen | Haoliang Wang | Ryan Rossi | Sungchul Kim | Anup Rao | Julian McAuley
Proceedings of the 62nd Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)

Large language models (LLMs) often require task-relevant knowledge to augment their internal knowledge through prompts. However, simply injecting external knowledge into prompts does not guarantee that LLMs can identify and use relevant information in the prompts to conduct chain-of-thought reasoning, especially when the LLM’s internal knowledge is derived from biased information on the pretraining data. In this paper, we propose a novel causal view to formally explain the internal knowledge bias of LLMs via a Structural Causal Model (SCM). We review the chain-of-thought (CoT) prompting from a causal perspective and discover that the biased information from pretrained models can impair LLMs’ reasoning abilities. When the CoT reasoning paths are misled by irrelevant information from prompts and are logically incorrect, simply editing factual information is insufficient to reach the correct answer. To estimate the confounding effect on CoT reasoning in LLMs, we use external knowledge as an instrumental variable. We further introduce CoT as a mediator to conduct front-door adjustment and generate logically correct CoTs where the spurious correlation between LLMs’ pretrained knowledge and task queries is reduced. With extensive experiments, we validate that our approach enables more accurate CoT reasoning and enhances LLM generation on knowledge-intensive tasks.

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Few-Shot Dialogue Summarization via Skeleton-Assisted Prompt Transfer in Prompt Tuning
Kaige Xie | Tong Yu | Haoliang Wang | Junda Wu | Handong Zhao | Ruiyi Zhang | Kanak Mahadik | Ani Nenkova | Mark Riedl
Proceedings of the 18th Conference of the European Chapter of the Association for Computational Linguistics (Volume 1: Long Papers)

In real-world scenarios, labeled samples for dialogue summarization are usually limited (i.e., few-shot) due to high annotation costs for high-quality dialogue summaries. To efficiently learn from few-shot samples, previous works have utilized massive annotated data from other downstream tasks and then performed prompt transfer in prompt tuning so as to enable cross-task knowledge transfer. However, existing general-purpose prompt transfer techniques lack consideration for dialogue-specific information. In this paper, we focus on improving the prompt transfer from dialogue state tracking to dialogue summarization and propose Skeleton-Assisted Prompt Transfer (SAPT), which leverages skeleton generation as extra supervision that functions as a medium connecting the distinct source and target task and resulting in the model’s better consumption of dialogue state information. To automatically extract dialogue skeletons as supervised training data for skeleton generation, we design a novel approach with perturbation-based probes requiring neither annotation effort nor domain knowledge. Training the model on such skeletons can also help preserve model capability during prompt transfer. Our method significantly outperforms existing baselines. In-depth analyses demonstrate the effectiveness of our method in facilitating cross-task knowledge transfer in few-shot dialogue summarization.

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Personalized Federated Learning for Text Classification with Gradient-Free Prompt Tuning
Rui Wang | Tong Yu | Ruiyi Zhang | Sungchul Kim | Ryan Rossi | Handong Zhao | Junda Wu | Subrata Mitra | Lina Yao | Ricardo Henao
Findings of the Association for Computational Linguistics: NAACL 2024

In this paper, we study personalized federated learning for text classification with Pretrained Language Models (PLMs). We identify two challenges in efficiently leveraging PLMs for personalized federated learning: 1) Communication. PLMs are usually large in size, e.g., with hundreds of millions of parameters, inducing huge communication cost in a federated setting. 2) Local Training. Training with PLMs generally requires back-propagation, during which memory consumption can be several times that of the forward-propagation. This may not be affordable when the PLMs are trained locally on the clients that are resource constrained, e.g., mobile devices with limited access to memory resources. Additionally, the proprietary PLMs can be provided as concealed APIs, for which the back-propagation operations may not be available. In solving these, we propose a training framework that includes an approach of discrete local search for gradient-free local training, along with a compression mechanism inspired from the linear word analogy that allows communicating with discretely indexed tokens, thus significantly reducing the communication cost. Experiments show that our gradient-free framework achieves superior performance compared with baselines.

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InstructGraph: Boosting Large Language Models via Graph-centric Instruction Tuning and Preference Alignment
Jianing Wang | Junda Wu | Yupeng Hou | Yao Liu | Ming Gao | Julian McAuley
Findings of the Association for Computational Linguistics: ACL 2024

Do current large language models (LLMs) better solve graph reasoning and generation tasks with parameter updates? In this paper, we propose InstructGraph, a framework that empowers LLMs with the abilities of graph reasoning and generation by instruction tuning and preference alignment. Specifically, we first propose a structured format verbalizer to unify all graph data into a universal code-like format, which can simply represent the graph without any external graph-specific encoders. Furthermore, a graph instruction tuning stage is introduced to guide LLMs in solving graph reasoning and generation tasks. Finally, we identify potential hallucination problems in graph tasks and sample negative instances for preference alignment, the target of which is to enhance the output’s reliability of the model. Extensive experiments across multiple graph-centric tasks exhibit that InstructGraph can achieve the best performance and outperform GPT-4 and LLaMA2 by more than 13% and 38%, respectively.

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FUTGA: Towards Fine-grained Music Understanding through Temporally-enhanced Generative Augmentation
Junda Wu | Zachary Novack | Amit Namburi | Jiaheng Dai | Hao-Wen Dong | Zhouhang Xie | Carol Chen | Julian McAuley
Proceedings of the 3rd Workshop on NLP for Music and Audio (NLP4MusA)

We propose FUTGA, a model equipped with fined-grained music understanding capabilities through learning from generative augmentation with temporal compositions. We leverage existing music caption datasets and large language models (LLMs) to synthesize fine-grained music captions with structural descriptions and time boundaries for full-length songs. Augmented by the proposed synthetic dataset, FUTGA is enabled to identify the music’s temporal changes at key transition points and their musical functions, as well as generate detailed descriptions for each music segment. We further introduce a full-length music caption dataset generated by FUTGA, as the augmentation of the MusicCaps and the Song Describer datasets. The experiments demonstrate the better quality of the generated captions, which capture the time boundaries of long-form music.

2023

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Federated Domain Adaptation for Named Entity Recognition via Distilling with Heterogeneous Tag Sets
Rui Wang | Tong Yu | Junda Wu | Handong Zhao | Sungchul Kim | Ruiyi Zhang | Subrata Mitra | Ricardo Henao
Findings of the Association for Computational Linguistics: ACL 2023

Federated learning involves collaborative training with private data from multiple platforms, while not violating data privacy. We study the problem of federated domain adaptation for Named Entity Recognition (NER), where we seek to transfer knowledge across different platforms with data of multiple domains. In addition, we consider a practical and challenging scenario, where NER datasets of different platforms of federated learning are annotated with heterogeneous tag sets, i.e., different sets of entity types. The goal is to train a global model with federated learning, such that it can predict with a complete tag set, i.e., with all the occurring entity types for data across all platforms. To cope with the heterogeneous tag sets in a multi-domain setting, we propose a distillation approach along with a mechanism of instance weighting to facilitate knowledge transfer across platforms. Besides, we release two re-annotated clinic NER datasets, for testing the proposed method in the clinic domain. Our method shows superior empirical performance for NER with federated learning.

2022

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Context-aware Information-theoretic Causal De-biasing for Interactive Sequence Labeling
Junda Wu | Rui Wang | Tong Yu | Ruiyi Zhang | Handong Zhao | Shuai Li | Ricardo Henao | Ani Nenkova
Findings of the Association for Computational Linguistics: EMNLP 2022

Supervised training of existing deep learning models for sequence labeling relies on large scale labeled datasets. Such datasets are generally created with crowd-source labeling. However, crowd-source labeling for tasks of sequence labeling can be expensive and time-consuming. Further, crowd-source labeling by external annotators may not be appropriate for data that contains user private information. Considering the above limitations of crowd-source labeling, we study interactive sequence labeling that allows training directly with the user feedback, which alleviates the annotation cost and maintains the user privacy. We identify two bias, namely, context bias and feedback bias, by formulating interactive sequence labeling via a Structural Causal Model (SCM). To alleviate the context and feedback bias based on the SCM, we identify the frequent context tokens as confounders in the backdoor adjustment and further propose an entropy-based modulation that is inspired by information theory. entities more sample-efficiently. With extensive experiments, we validate that our approach can effectively alleviate the biases and our models can be efficiently learnt with the user feedback.