Zixuan Ke

dblp:196/3817 · DBLP profile ↗
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22ranked-venue papers
13as first author
16since 2021 · last 2025
—ORCID · none

Domains — the database's venue-derived domains; a paper can count in several

Artificial intelligence and machine learning · 21 · 13 first-author · 15 since 2021Databases, data management, data science and information retrieval · 2 · 1 first-author · 1 since 2021Graphics, computer vision, multimedia, augmented reality and games · 2 · 2 first-author
YearPublicationVenuePosition
2025 In-context Continual Learning Assisted by an External Continual Learner
abstract
Existing continual learning (CL) methods mainly rely on fine-tuning or adapting large language models (LLMs). They still suffer from catastrophic forgetting (CF). Little work has been done to exploit in-context learning (ICL) to leverage the extensive knowledge within LLMs for CL without updating any parameters. However, incrementally learning each new task in ICL necessitates adding training examples from each class of the task to the prompt, which hampers scalability as the prompt length increases. This issue not only leads to excessively long prompts that exceed the input token limit of the underlying LLM but also degrades the model’s performance due to the overextended context. To address this, we introduce InCA, a novel approach that integrates an external continual learner (ECL) with ICL to enable scalable CL without CF. The ECL is built incrementally to pre-select a small subset of likely classes for each test instance. By restricting the ICL prompt to only these selected classes, InCA prevents prompt lengths from becoming excessively long, while maintaining high performance. Experimental results demonstrate that InCA significantly outperforms existing CL baselines, achieving substantial performance gains.
Saleh Momeni, Sahisnu Mazumder, Zixuan Ke, Bing Liu 0001
COLING3
2025 Continual Learning Using Only Large Language Model Prompting
abstract
We introduce CLOB, a novel continual learning (CL) paradigm wherein a large language model (LLM) is regarded as a black box. Learning is done incrementally via only verbal prompting. CLOB does not fine-tune any part of the LLM or add any trainable parameters to it. It is particularly suitable for LLMs that are accessible via APIs. We also propose a new CL technique, called CIS, based on incremental summarization that also overcomes the LLM’s input length limit. Experiments show CIS outperforms baselines by a very large margin.
Jiabao Qiu, Zixuan Ke, Bing Liu 0001
COLING2
2025 Demystifying Domain-adaptive Post-training for Financial LLMs
abstract
Domain-adaptive post-training of large language models (LLMs) has emerged as a promising approach for specialized domains such as medicine and finance.However, significant challenges remain in identifying optimal adaptation criteria and training strategies across varying data and model configurations.To address these challenges, we introduce FINDAP, a systematic and fine-grained investigation into domain-adaptive post-training of LLMs for the finance domain.Our approach consists of four key components: FinCap, which defines the core capabilities required for the target domain; FinRec, an effective training recipe that jointly optimizes continual pre-training and instruction-following, along with a novel preference data distillation method leveraging process signals from a generative reward model; FinTrain, a curated set of training datasets supporting FinRec; and FinEval, a comprehensive evaluation suite aligned with FinCap.The resulting model, Llama-Fin, achieves state-ofthe-art performance across a wide range of financial tasks.Our analysis also highlights how each post-training stage contributes to distinct capabilities, uncovering specific challenges and effective solutions, providing valuable insights for domain adaptation of LLMs.
Zixuan Ke, Yifei Ming, Xuan-Phi Nguyen, Caiming Xiong, Shafiq R. Joty
EMNLP1
2025 FaithEval: Can Your Language Model Stay Faithful to Context, Even If "The Moon is Made of Marshmallows"
abstract
Ensuring faithfulness to context in large language models (LLMs) and retrieval-augmented generation (RAG) systems is crucial for reliable deployment in real-world applications, as incorrect or unsupported information can erode user trust. Despite advancements on standard benchmarks, faithfulness hallucination—where models generate responses misaligned with the provided context—remains a significant challenge. In this work, we introduce FaithEval, a novel and comprehensive benchmark tailored to evaluate the faithfulness of LLMs in contextual scenarios across three diverse tasks: unanswerable, inconsistent, and counterfactual contexts. These tasks simulate real-world challenges where retrieval mechanisms may surface incomplete, contradictory, or fabricated information. FaithEval comprises 4.9K high-quality problems in total, validated through a rigorous four-stage context construction and validation framework, employing both LLM-based auto-evaluation and human validation. Our extensive study across a wide range of open-source and proprietary models reveals that even state-of-the-art models often struggle to remain faithful to the given context, and that larger models do not necessarily exhibit improved faithfulness. Code is available at: https://github.com/SalesforceAIResearch/FaithEval.
Yifei Ming, Senthil Purushwalkam, Shrey Pandit, Zixuan Ke, Xuan-Phi Nguyen, Caiming Xiong, Shafiq R. Joty
ICLR4
2025 Beyond Accuracy: Dissecting Mathematical Reasoning for LLMs Under Reinforcement Learning
abstract
Reinforcement learning (RL) has become the dominant paradigm for improving the performance of language models on complex reasoning tasks. Despite the substantial empirical gains demonstrated by RL-based training methods like GRPO, a granular understanding of why and how RL enhances performance is still lacking. To bridge this gap, we introduce SPARKLE, a fine-grained analytic framework to dissect the effects of RL across three key dimensions: (1) plan following and execution, (2) knowledge integration, and (3) chain of subproblems. Using this framework, we gain insights beyond mere accuracy. For instance, providing models with explicit human-crafted, step-by-step plans can surprisingly degrade performance on the most challenging benchmarks, yet RL-tuned models exhibit greater robustness, experiencing markedly smaller performance drops than base or SFT models. This suggests that RL may not primarily enhance the execution of external plans but rather empower models to formulate and follow internal strategies better suited to their reasoning processes. Conversely, we observe that RL enhances models' ability to integrate provided knowledge into their reasoning process, yielding consistent gains across diverse tasks. Finally, we study whether difficult problems---those yielding no RL signals and mixed-quality reasoning traces---can still be effectively used for training. We introduce SparkleRL-PSS, a multi-stage RL pipeline that reuses hard problems with partial step scaffolding, guiding exploration effectively without additional data generation. Together, our findings provide a principled foundation for understanding how RL shapes model behavior, offering practical insights for building more adaptive, data-efficient, and interpretable RL pipelines for reasoning tasks. Our code, data, and checkpoints are available at: https://sparkle-reasoning.github.io/.
Yifei Ming, Zixuan Ke, Caiming Xiong, Shafiq R. Joty, Aws Albarghouthi, Frederic Sala
NeurIPS3
2025 Open-world continual learning: Unifying novelty detection and continual learning
Gyuhak Kim, Changnan Xiao, Tatsuya Konishi, Zixuan Ke, Bing Liu 0001
Artif. Intell.4
2024 Bridging the Preference Gap between Retrievers and LLMs
abstract
Large Language Models (LLMs) have demonstrated superior results across a wide range of tasks, and Retrieval-augmented Generation (RAG) is an effective way to enhance the performance by locating relevant information and placing it into the context window of the LLM.However, the relationship between retrievers and LLM in a RAG is still under-investigated.Most existing work treats the retriever and the LLM as independent components and leaves a gap between retrieving human-"friendly" information and assembling a LLM-"friendly" context.In this work, we examine a novel bridge mechanism.We validate the ranking and selection assumptions of retrievers in the context of RAG and propose a framework that chains together supervised and reinforcement learning to train a bridge model that optimizes the connection between the retriever and the LLM.Empirical results demonstrate the effectiveness of our method in both questionanswering and personalized generation tasks.
Zixuan Ke, Weize Kong, Cheng Li 0012, Mingyang Zhang 0001, Qiaozhu Mei, Michael Bendersky
ACL (1)1
2023 Continual Pre-training of Language Models
Zixuan Ke, Yijia Shao, Haowei Lin, Tatsuya Konishi, Gyuhak Kim, Bing Liu 0001
ICLR1
2023 Parameter-Level Soft-Masking for Continual Learning
abstract
Existing research on task incremental learning in continual learning has primarily focused on preventing catastrophic forgetting (CF). Although several techniques have achieved learning with no CF, they attain it by letting each task monopolize a sub-network in a shared network, which seriously limits knowledge transfer (KT) and causes over-consumption of the network capacity, i.e., as more tasks are learned, the performance deteriorates. The goal of this paper is threefold: (1) overcoming CF, (2) encouraging KT, and (3) tackling the capacity problem. A novel technique (called SPG) is proposed that soft-masks (partially blocks) parameter updating in training based on the importance of each parameter to old tasks. Each task still uses the full network, i.e., no monopoly of any part of the network by any task, which enables maximum KT and reduction in capacity usage. To our knowledge, this is the first work that soft-masks a model at the parameter-level for continual learning. Extensive experiments demonstrate the effectiveness of SPG in achieving all three objectives. More notably, it attains significant transfer of knowledge not only among similar tasks (with shared knowledge) but also among dissimilar tasks (with little shared knowledge) while mitigating CF.
Tatsuya Konishi, Mori Kurokawa, Chihiro Ono, Zixuan Ke, Gyuhak Kim, Bing Liu 0001
ICML4
2022 Continual Training of Language Models for Few-Shot Learning
abstract
Recent work on applying large language models (LMs) achieves impressive performance in many NLP applications.Adapting or posttraining an LM using an unlabeled domain corpus can produce even better performance for end-tasks in the domain.This paper proposes the problem of continually extending an LM by incrementally post-train the LM with a sequence of unlabeled domain corpora to expand its knowledge without forgetting its previous skills.The goal is to improve the few-shot end-task learning in these domains.The resulting system is called CPT (Continual Post-Training), which to our knowledge, is the first continual post-training system.Experimental results verify its effectiveness.
Zixuan Ke, Haowei Lin, Yijia Shao, Hu Xu 0001, Lei Shu 0004, Bing Liu 0001
EMNLP1
2022 Adapting a Language Model While Preserving its General Knowledge
abstract
Domain-adaptive pre-training (or DA-training for short), also known as post-training, aims to train a pre-trained general-purpose language model (LM) using an unlabeled corpus of a particular domain to adapt the LM so that endtasks in the domain can give improved performances.However, existing DA-training methods are in some sense blind as they do not explicitly identify what knowledge in the LM should be preserved and what should be changed by the domain corpus.This paper shows that the existing methods are suboptimal and proposes a novel method to perform a more informed adaptation of the knowledge in the LM by (1) soft-masking the attention heads based on their importance to best preserve the general knowledge in the LM and (2) contrasting the representations of the general and the full (both general and domain knowledge) to learn an integrated representation with both general and domain-specific knowledge.Experimental results will demonstrate the effectiveness of the proposed approach.1
Zixuan Ke, Yijia Shao, Haowei Lin, Hu Xu 0001, Lei Shu 0004, Bing Liu 0001
EMNLP1
2022 A Theoretical Study on Solving Continual Learning
abstract
Continual learning (CL) learns a sequence of tasks incrementally. There are two popular CL settings, class incremental learning (CIL) and task incremental learning (TIL). A major challenge of CL is catastrophic forgetting (CF). While a number of techniques are already available to effectively overcome CF for TIL, CIL remains to be highly challenging. So far, little theoretical study has been done to provide a principled guidance on how to solve the CIL problem. This paper performs such a study. It first shows that probabilistically, the CIL problem can be decomposed into two sub-problems: Within-task Prediction (WP) and Task-id Prediction (TP). It further proves that TP is correlated with out-of-distribution (OOD) detection, which connects CIL and OOD detection. The key conclusion of this study is that regardless of whether WP and TP or OOD detection are defined explicitly or implicitly by a CIL algorithm, good WP and good TP or OOD detection are necessary and sufficient for good CIL performances. Additionally, TIL is simply WP. Based on the theoretical result, new CIL methods are also designed, which outperform strong baselines in both CIL and TIL settings by a large margin.
Gyuhak Kim, Changnan Xiao, Tatsuya Konishi, Zixuan Ke, Bing Liu 0001
NeurIPS4
2022 Partially Relaxed Masks for Knowledge Transfer Without Forgetting in Continual Learning
Tatsuya Konishi, Mori Kurokawa, Chihiro Ono, Zixuan Ke, Gyuhak Kim, Bing Liu 0001
PAKDD (1)4
2021 CLASSIC: Continual and Contrastive Learning of Aspect Sentiment Classification Tasks
abstract
This paper studies continual learning (CL) of a sequence of aspect sentiment classification (ASC) tasks in a particular CL setting called domain incremental learning (DIL). Each task is from a different domain or product. The DIL setting is particularly suited to ASC because in testing the system needs not know the task/domain to which the test data belongs. To our knowledge, this setting has not been studied before for ASC. This paper proposes a novel model called CLASSIC. The key novelty is a contrastive continual learning method that enables both knowledge transfer across tasks and knowledge distillation from old tasks to the new task, which eliminates the need for task ids in testing. Experimental results show the high effectiveness of CLASSIC.
Zixuan Ke, Bing Liu 0001, Hu Xu 0001, Lei Shu 0004
EMNLP (1)1
2021 Adapting BERT for Continual Learning of a Sequence of Aspect Sentiment Classification Tasks
abstract
This paper studies continual learning (CL) of a sequence of aspect sentiment classification (ASC) tasks.Although some CL techniques have been proposed for document sentiment classification, we are not aware of any CL work on ASC.A CL system that incrementally learns a sequence of ASC tasks should address the following two issues: (1) transfer knowledge learned from previous tasks to the new task to help it learn a better model, and (2) maintain the performance of the models for previous tasks so that they are not forgotten.This paper proposes a novel capsule network based model called B-CL to address these issues.B-CL markedly improves the ASC performance on both the new task and the old tasks via forward and backward knowledge transfer.The effectiveness of B-CL is demonstrated through extensive experiments.1
Zixuan Ke, Hu Xu 0001, Bing Liu 0001
NAACL-HLT1
2021 Achieving Forgetting Prevention and Knowledge Transfer in Continual Learning
abstract
Continual learning (CL) learns a sequence of tasks incrementally with the goal of achieving two main objectives: overcoming catastrophic forgetting (CF) and encouraging knowledge transfer (KT) across tasks. However, most existing techniques focus only on overcoming CF and have no mechanism to encourage KT, and thus do not do well in KT. Although several papers have tried to deal with both CF and KT, our experiments show that they suffer from serious CF when the tasks do not have much shared knowledge. Another observation is that most current CL methods do not use pre-trained models, but it has been shown that such models can significantly improve the end task performance. For example, in natural language processing, fine-tuning a BERT-like pre-trained language model is one of the most effective approaches. However, for CL, this approach suffers from serious CF. An interesting question is how to make the best use of pre-trained models for CL. This paper proposes a novel model called CTR to solve these problems. Our experimental results demonstrate the effectiveness of CTR
Zixuan Ke, Bing Liu 0001, Nianzu Ma, Hu Xu 0001, Lei Shu 0004
NeurIPS1
2020 Continual Learning of a Mixed Sequence of Similar and Dissimilar Tasks
abstract
Existing research on continual learning of a sequence of tasks focused on dealing with catastrophic forgetting, where the tasks are assumed to be dissimilar and have little shared knowledge. Some work has also been done to transfer previously learned knowledge to the new task when the tasks are similar and have shared knowledge. %However, in the most general case, a CL system not only should have the above two capabilities, but also the \textit{backward knowledge transfer} capability so that future tasks may help improve the past models whenever possible. To the best of our knowledge, no technique has been proposed to learn a sequence of mixed similar and dissimilar tasks that can deal with forgetting and also transfer knowledge forward and backward. This paper proposes such a technique to learn both types of tasks in the same network. For dissimilar tasks, the algorithm focuses on dealing with forgetting, and for similar tasks, the algorithm focuses on selectively transferring the knowledge learned from some similar previous tasks to improve the new task learning. Additionally, the algorithm automatically detects whether a new task is similar to any previous tasks. Empirical evaluation using sequences of mixed tasks demonstrates the effectiveness of the proposed model.
Zixuan Ke, Bing Liu 0001, Xingchang Huang
NeurIPS1
2020 Continual Learning with Knowledge Transfer for Sentiment Classification
Zixuan Ke, Bing Liu 0001, Hao Wang 0008, Lei Shu 0004
ECML/PKDD (3)1
2019 Give Me More Feedback II: Annotating Thesis Strength and Related Attributes in Student Essays
abstract
While the vast majority of existing work on automated essay scoring has focused on holistic scoring, researchers have recently begun work on scoring specific dimensions of essay quality.Nevertheless, progress in dimensionspecific essay scoring research is hindered in part by the lack of annotated corpora.To facilitate advances in this area of research, we design a rubric for scoring an important, yet unexplored dimension of persuasive essay quality, thesis strength, and annotate a corpus of essays with thesis strength scores.We additionally identify the attributes that could impact thesis strength and annotate the essays with the values of these attributes, which, when predicted by computational models, could provide feedback to students on why her essay receives a particular thesis strength score.
Zixuan Ke, Hrishikesh Inamdar, Vincent Ng 0001
ACL (1)1
2019 Automated Essay Scoring: A Survey of the State of the Art
abstract
Despite being investigated for over 50 years, the task of automated essay scoring is far from being solved. Nevertheless, it continues to draw a lot of attention in the natural language processing community in part because of its commercial and educational values as well as the associated research challenges. This paper presents an overview of the major milestones made in automated essay scoring research since its inception.
Zixuan Ke, Vincent Ng 0001
IJCAI1
2018 Give Me More Feedback: Annotating Argument Persuasiveness and Related Attributes in Student Essays
abstract
While argument persuasiveness is one of the most important dimensions of argumentative essay quality, it is relatively little studied in automated essay scoring research.Progress on scoring argument persuasiveness is hindered in part by the scarcity of annotated corpora.We present the first corpus of essays that are simultaneously annotated with argument components, argument persuasiveness scores, and attributes of argument components that impact an argument's persuasiveness.This corpus could trigger the development of novel computational models concerning argument persuasiveness that provide useful feedback to students on why their arguments are (un)persuasive in addition to how persuasive they are.
Winston Carlile, Nishant Gurrapadi, Zixuan Ke, Vincent Ng 0001
ACL (1)3
2018 Learning to Give Feedback: Modeling Attributes Affecting Argument Persuasiveness in Student Essays
abstract
Argument persuasiveness is one of the most important dimensions of argumentative essay quality, yet it is little studied in automated essay scoring research. Using a recently released corpus of essays that are simultaneously annotated with argument components, argument persuasiveness scores, and attributes of argument components that impact an argument’s persuasiveness, we design and train the first set of neural models that predict the persuasiveness of an argument and its attributes in a student essay, enabling useful feedback to be provided to students on why their arguments are (un)persuasive in addition to how persuasive they are.
Zixuan Ke, Winston Carlile, Nishant Gurrapadi, Vincent Ng 0001
IJCAI1