Papers by Liwen Zhang

21 papers
SHARP: Search-Based Adversarial Attack for Structured Prediction (2022.findings-naacl)

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Challenge: SHARP is a new attack method for structured prediction models that solves several challenges.
Approach: They propose a black-box adversarial attack method that uses a search-based optimization problem to attack adversarials.
Outcome: The proposed method performs more potent attack than pioneer arts on two structured prediction tasks.
Gaussian Mixture Latent Vector Grammars (P18-1)

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Challenge: Existing models of latent variable grammars are not observable in treebanks, so latent variables are learned using expectation-maximization.
Approach: They propose a new framework that extends latent variable grammars such that each nonterminal symbol is associated with a continuous vector space representing the set of (infinitely many) subtypes of the nonterminals.
Outcome: The proposed framework can achieve competitive accuracies in part-of-speech tagging and constituency parsing.
RECALL: REpresentation-aligned Catastrophic-forgetting ALLeviation via Hierarchical Model Merging (2025.emnlp-main)

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Challenge: Existing models that require task labels or performance trade-offs are susceptible to catastrophic forgetting.
Approach: They propose a representation-aware model merging framework for continual learning without access to historical data.
Outcome: The proposed framework outperforms baselines in knowledge retention and generalization across five NLP tasks and multiple continual learning scenarios.
EDDA: An Encoder-Decoder Data Augmentation Framework for Zero-Shot Stance Detection (2024.lrec-main)

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Challenge: Existing methods for enhancing text or data are limited by lack of logical connections between generated texts and training data.
Approach: They propose an encoder-decoder data augmentation framework that combines large language models and chain-of-thought prompting to summarize texts into target-specific if-then rationales, establishing logical relationships.
Outcome: The proposed framework significantly improves over state-of-the-art methods on benchmark datasets while enabling interpretable rationale-based learning.
AISFG: Abundant Information Slot Filling Generator (2022.naacl-main)

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Challenge: Existing approaches to zero/few-shot slot filling focus on slot descriptions and examples . AISFG model is based on domain-specific labels, which is not capable of transferring to new domains with little or no data.
Approach: They propose a model with a query template that incorporates domain descriptions, slot descriptions, and examples with context.
Outcome: Experimental results show that the proposed model outperforms state-of-the-art approaches in zero/few-shot slot filling task.
FinSafetyBench: Evaluating LLM Safety in Real-World Financial Scenarios (2026.findings-acl)

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Challenge: Existing large language models (LLMs) are prone to misuse and misinformation, posing serious compliance risks.
Approach: They propose a bilingual red-teaming benchmark to test an LLM’s refusal of requests that violate financial compliance.
Outcome: The proposed benchmark is based on real-world financial crime cases and ethical violations and includes 14 subcategories covering financial crimes and ethical breaches.
EvolveSearch: An Iterative Self-Evolving Search Agent (2025.emnlp-main)

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Challenge: Existing approaches to enabling LLM web search proficiency struggle with data production in open-search domains, while supervised fine-tuning struggles with data utilization efficiency.
Approach: They propose an iterative self-evolution framework that combines SFT and RL to enhance agentic web search capabilities without external human-annotated reasoning data.
Outcome: EvolveSearch achieves 4.7% improvement over current state-of-the-art in seven benchmarks . supervised fine-tuning struggles with data production in open-search domains compared with RL .
Nested Browser-Use Learning for Agentic Information Seeking (2026.acl-long)

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Challenge: Existing information-seeking (IS) agents rely on the web for their information acquisition.
Approach: They propose a browser-action framework that decouples interaction control from page exploration through a nested structure.
Outcome: Empirical results show that NestBrowse offers clear benefits in practice.
Latent Variable Sentiment Grammar (P19-1)

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Challenge: Existing neural models do not explicitly model sentiment composition, which requires to encode sentiment class labels.
Approach: They propose a sentiment grammar that captures sentiment subtype expressions by latent variables and Gaussian mixture vectors.
Outcome: The proposed model outperforms vanilla neural encoders on the Stanford Sentiment Treebank benchmark.
Generalized Supervised Attention for Text Generation (2021.findings-acl)

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Challenge: Existing supervised attention methods that use human knowledge to learn better alignments are costly or infeasible.
Approach: They propose a generalized supervised attention method based on quasi alignments that are easier to obtain than ideal alignments.
Outcome: The proposed framework improves generation performance and is robust against errors in attention supervision.
WebAnchor: Anchoring Agent Planning to Stabilize Long-Horizon Web Reasoning (2026.findings-acl)

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Challenge: Existing methods for reinforcement learning (RL)-based agents struggle with long-horizon planning and strategy coherence.
Approach: They propose a reinforcement learning framework that decouples planning and execution.
Outcome: The proposed framework outperforms baseline and first-step RL frameworks on four benchmarks.
VisFinEval: A Scenario-Driven Chinese Multimodal Benchmark for Holistic Financial Understanding (2025.emnlp-main)

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Challenge: Existing benchmarks focus on text comprehension, but MLLMs lack the ability to integrate visual data over financial visuals.
Approach: They evaluate 21 state-of-the-art multimodal large language models in a zero-shot setting . they use an annotated question–answer pair from eight common financial image modalities .
Outcome: The new benchmark outperforms existing models but trailed financial experts by 14 percentage points.
Learning Multilingual Sentence Representations with Cross-lingual Consistency Regularization (2023.emnlp-industry)

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Challenge: Experimental results on multilingual similarity search and bitext mining tasks show the effectiveness of our approach.
Approach: They propose a multilingual sentence representation model that aligns different languages in a shared representation space.
Outcome: The proposed model performs better than LASER3 on similarity searches and bitext mining tasks.
Evidence Retrieval is almost All You Need for Fact Verification (2024.findings-acl)

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Challenge: Existing evidence retrieval methods adopt a trivial retrieval strategy, resulting in task-irrelevant evidence and undesirable performance.
Approach: They propose a framework for evidence retrieval and joint fact verification that integrates two modules.
Outcome: The proposed framework improves evidence retrieval and claims verification on a FEVER dataset.
Adapting Unsupervised Syntactic Parsing Methodology for Discourse Dependency Parsing (2021.acl-long)

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Challenge: Discourse dependency parsing is a task that requires a large amount of training data, but there is little research on it.
Approach: They propose to adapt unsupervised syntactic dependency parsing methods for unsupervised discourse dependency parses using unlabeled training data.
Outcome: The proposed methods outperform existing methods in semi-supervised and supervised settings and outperformed existing methods.
Improving Zero-shot Multilingual Neural Machine Translation by Leveraging Cross-lingual Consistency Regularization (2023.findings-acl)

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Challenge: Existing methods to improve zero-shot translation performance by learning language-agnostic representations and maximizing cross-lingual transfer have been proposed.
Approach: They propose a cross-lingual consistency regularization to bridge the representation gap between different languages and boost zero-shot translation performance.
Outcome: The proposed model improves translation performance on low-resource and high-res benchmarks and closes the sentence representation gap and aligns the representation space.
Adversarial Attack and Defense of Structured Prediction Models (2020.emnlp-main)

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Challenge: Existing approaches to building effective adversarial attackers focus on classification problems.
Approach: They propose a framework that learns to attack a structured prediction model with feedbacks from multiple reference models.
Outcome: The proposed framework is able to attack state-of-the-art models and boost them with training . it is based on a sequence-to-sequence model with feedbacks from multiple reference models .
Sentiment Interpretable Logic Tensor Network for Aspect-Term Sentiment Analysis (2022.coling-1)

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Challenge: Aspect-term sentiment analysis (ATSA) is a fine-grained task that aims to infer the sentiment towards the given aspect-terms.
Approach: They propose a novel ATSA method that is interpretable and has high accuracy . they propose SILTN, which is a neurosymbolic formalism, to improve the accuracy based on syntax knowledge distillation.
Outcome: The proposed method is interpretable because it is a neurosymbolic formalism and a computational model that supports learning and reasoning about data with a differentiable first-order logic language.
BrowseConf: Confidence-Guided Test-Time Scaling for Web Agents (2026.findings-acl)

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Challenge: Existing work on confidence in LLMs is limited.
Approach: They propose to use confidence scores to determine model answer quality and encourage model to try again until it reaches satisfactory confidence level.
Outcome: The proposed methods significantly reduce token consumption while demonstrating competitive performance compared to baseline fixed budget methods.
FinEval: A Chinese Financial Domain Knowledge Evaluation Benchmark for Large Language Models (2025.naacl-long)

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Challenge: Large language models have demonstrated outstanding performance in various natural language processing tasks, but their security capabilities in the financial domain have not been explored.
Approach: They propose to use a benchmark to evaluate large language models' financial domain knowledge and practical abilities.
Outcome: The proposed benchmark evaluates large language models' financial domain knowledge and practical abilities.
Query Routing for Homogeneous Tools: An Instantiation in the RAG Scenario (2024.findings-emnlp)

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Challenge: Existing tool learning methods focus on selecting the most effective tool from a wide array of options, often overlooking cost-effectiveness.
Approach: They propose to predict query performance and cost required to accomplish a given task . they then assign queries to the optimal tools in a cost-effective manner .
Outcome: The proposed method achieves higher performance at lower cost compared to baseline approaches.

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