Xiang Liu
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2026
EVOQUANT: Self-Evolving Verifier-Guided Strategy Optimization for Robust Quantitative Trading
Jie Mao | Changlun Li | Xiang Li | Qiqi Duan | Jinhui Yuan | Xiang Liu | Yuyu Luo | Jing Tang | Nan Tang
Proceedings of the 11th Workshop on Financial Technology and Natural Language Processing
Jie Mao | Changlun Li | Xiang Li | Qiqi Duan | Jinhui Yuan | Xiang Liu | Yuyu Luo | Jing Tang | Nan Tang
Proceedings of the 11th Workshop on Financial Technology and Natural Language Processing
Quantitative strategy optimization remains largely manual, requiring domain experts to identify weak signals, tune risk-control rules, and repeatedly validate iterative revisions. Large language models can accelerate this process, but directly relying on them to rewrite trading strategies often introduces hallucinated edits, strategy drift, and back-test overfitting. We propose EVOQUANT, a self-evolving verifier-guided framework for strategy optimization in quantitative trading. Our method utilizes LLMs to deeply diagnose performance bottlenecks, generate semantically controlled candidate edits, select the best strategy through a multi-stage verification pipeline, and distill optimization experience into reusable knowledge for continual self-improvement. We evaluate our method using seven representative strategies: four from the A-share market and three from the crypto market. Experimental results show that our method significantly improves the Sharpe ratio across all tested strategies: the average test Sharpe increases from −0.298 to 0.538, and the best-performing strategy achieves a 199% relative improvement. Ablation studies and stress tests under stricter conditions further validate the effectiveness and robustness of the framework. Overall, this work transforms quantitative strategy optimization from costly manual trial-and-error into an automated and verifiable iterative paradigm, offering a new path for applying large language models to financial strategy research.
Probing the Plasticity and Correlation of LLM Value Systems: LLM Value Rankings are Not Stable
Zhenheng Tang | Qihua Pan | Jingya Shen | Xiang Liu | Qian Wang | Bo Li | Xiaowen Chu
Findings of the Association for Computational Linguistics: ACL 2026
Zhenheng Tang | Qihua Pan | Jingya Shen | Xiang Liu | Qian Wang | Bo Li | Xiaowen Chu
Findings of the Association for Computational Linguistics: ACL 2026
The value alignment of Large Language Models (LLMs) is critical because value is the foundation of LLM decision-making and behavior. Some recent work show that LLMs have similar value rankings. However, little is known about how susceptible LLM value rankings are to external influence and how different values are correlated with each other. In this work, we investigate the plasticity of LLM value systems by examining how their value rankings are influenced by different prompting strategies and exploring the intrinsic relationships between values. To this end, we design 6 different value transformation prompting methods including direct instruction, rubrics, in-context learning, scenario, persuasion, and persona, and benchmark the effectiveness of these methods on 3 different families and totally 8 LLMs. Our main findings include that the value rankings in large LLMs are much more susceptible to external influence than small LLMs, and there are intrinsic correlations between certain values (e.g., Privacy and Respect). Besides, through detailed correlation analysis, we find that the value correlations are more similar between large LLMs of different families than small LLMs of the same family. We also identify that scenario method is the strongest persuader and can help entrench the value rankings.
From Saliency Ranking to Evidence Preservation: Visual Token Condensation for Efficient Multimodal Reasoning
Xin Zou | Di Lu | Yibo Yan | Shuliang Liu | Yizhou Wang | Xiang Liu | Linfeng Zhang | Xuming Hu
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Xin Zou | Di Lu | Yibo Yan | Shuliang Liu | Yizhou Wang | Xiang Liu | Linfeng Zhang | Xuming Hu
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Visual tokens dominate the inference cost of multimodal large language models (MLLMs), but aggressive token reduction often degrades reasoning. We argue that the fragility comes from a saliency-ranking view, i.e., existing training-free methods typically rank tokens by a scalar proxy, such as cross-attention, [CLS] attention, or feature similarity, and then prune or merge tokens independently. However, visual evidence is set-valued and structured: salient patches can be redundant, low-saliency tokens can be answer-critical, and feature-similar patches can be unsafe to merge when they are spatially incompatible. We propose CondenseVLM, a simple framework that formulates visual token compression as a budgeted evidence-preservation question. The formulation jointly optimizes salient evidence coverage, contextual coverage, and spatially constrained merge fidelity. It yields a monotone submodular coverage term, a marginal-gain interpretation of diversity-aware anchor selection, and a local distortion bound for spatial-semantic merging. Comprehensive experiments across six MLLM families and diverse general-purpose, grounding, text-dense, and video benchmarks demonstrate that improves the accuracy-efficiency trade-off, and achieves the SOTA performance.
NestedKV: Nested Memory Routing for Long-Context KV Cache Compression
Hong Chen | Xiang Liu | Yubo Gao | Yuxuan Fan | Bo Wang | Yuanlin Chu | Yuanguo Lin | Xuming Hu
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Hong Chen | Xiang Liu | Yubo Gao | Yuxuan Fan | Bo Wang | Yuanlin Chu | Yuanguo Lin | Xuming Hu
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Long-context language models are limited by the memory footprint of the key-value (KV) cache. Existing training-free KV compression methods usually rank tokens by one importance signal — attention, recency, layer-wise allocation, or key distinctiveness — which becomes brittle when useful context is globally distinctive, locally episodic, or immediately relevant. We introduce NestedKV, a key-only KV cache compression method inspired by the Continuum Memory System in Nested Learning. NestedKV maintains global, block-level, and sliding-window key anchors, scores tokens by multi-time-scale cosine anomaly, and combines the resulting rankings with a training-free outer learner using head-adaptive mixing and surprise-gated token routing. The score is paired with adaptive per-head budgets and requires no training or LLM modification. Across RULER (4k–32k), LooGLE, LongBench, LongBench-E, InfiniteBench, and MMLU-Pro on Qwen3 and Llama-3.2 models, NestedKV is strongest when the retained cache is small. On Qwen3-4B, it improves over KeyDiff by up to 19.10 points on RULER and 19.29 on LongBench at r=0.75; at r=0.95, it retains 37.32 on LongBench versus 17.55 for KeyDiff.
CAFES: A Collaborative Multi-Agent Framework for Multi-Granular Multimodal Essay Scoring
Jiamin Su | Yibo Yan | Zhuoran Gao | Han Zhang | Xiang Liu | Huiyu Zhou | Xuming Hu
Proceedings of the 4th Workshop on Advances in Language and Vision Research (ALVR)
Jiamin Su | Yibo Yan | Zhuoran Gao | Han Zhang | Xiang Liu | Huiyu Zhou | Xuming Hu
Proceedings of the 4th Workshop on Advances in Language and Vision Research (ALVR)
Automated Essay Scoring (AES) is crucial for modern education, particularly with the increasing prevalence of multimodal assessments. However, traditional AES methods struggle with evaluation generalizability and multimodal perception, while even recent Multimodal Large Language Model (MLLM)-based approaches can produce hallucinated justifications and scores misaligned with human judgment. To address the limitations, we introduce CAFES, the first collaborative multi-agent framework specifically designed for AES. It orchestrates three specialized agents: an Initial Scorer for rapid, trait-specific evaluations; a Feedback Pool Manager to aggregate detailed and evidence-grounded feedback; and a Reflective Scorer that iteratively refines scores based on this feedback to enhance human alignment. Extensive experiments, using widely adopted MLLMs, achieve an average relative improvement of 21% in Quadratic Weighted Kappa (QWK) against ground truth, with particularly strong gains in grammatical and lexical diversity. Our proposed CAFES paves the way for an intelligent multimodal AES system. The code and dataset are available at https://anonymous.4open.science/r/CAFES-C87F/.
Llm agent memory: a survey from a unified representation–management perspective
Zhenheng Tang | Xin He | Tiancheng Zhao | Fanjunduo Wei | Xiang Liu | Peijie Dong | Qian Wang | Qi Li | Huacan Wang | Ronghao Chen | Sen Hu | Weidong Guo | Yu Xu | Haolan Chen | Kunfeng Lai | Kaiyong Zhao | Keyan Ding | Ivor Tsang | Yew-Soon Ong | Bo Li | Xiaowen Chu
Proceedings of the 15th International Joint Conference on Natural Language Processing and the 5th Conference of the Asia-Pacific Chapter of the Association for Computational Linguistics (Volume 1: Long Papers)
Zhenheng Tang | Xin He | Tiancheng Zhao | Fanjunduo Wei | Xiang Liu | Peijie Dong | Qian Wang | Qi Li | Huacan Wang | Ronghao Chen | Sen Hu | Weidong Guo | Yu Xu | Haolan Chen | Kunfeng Lai | Kaiyong Zhao | Keyan Ding | Ivor Tsang | Yew-Soon Ong | Bo Li | Xiaowen Chu
Proceedings of the 15th International Joint Conference on Natural Language Processing and the 5th Conference of the Asia-Pacific Chapter of the Association for Computational Linguistics (Volume 1: Long Papers)
Large language models (LLMs) face significant challenges in sustaining long-term memory for agentic applications due to limited context windows. To address this limitation, many work has proposed diverse memory mechanisms to support long-term, multi-turn interactions, leveraging different approaches tailored to distinct memory storage objects, such as KV caches. In this survey, we present a unified taxonomy that organizes memory systems for long-context scenarios by decoupling memory abstractions from model-specific inference and training methods. We categorize LLM memory into three primary paradigms: natural language tokens, intermediate representations and parameters. For each paradigm, we organize existing methods by three management stages, including memory construction, update, and query, so that long-context memory mechanisms can be described in a consistent way across system designs, with their implementation choices and constraints made explicit. Finally, we outline key research directions for long-context memory system design.
2025
Perovskite-LLM: Knowledge-Enhanced Large Language Models for Perovskite Solar Cell Research
Xiang Liu | Penglei Sun | Shuyan Chen | Longhan Zhang | Peijie Dong | Huajie You | Yongqi Zhang | Chang Yan | Xiaowen Chu | Tong-yi Zhang
Findings of the Association for Computational Linguistics: EMNLP 2025
Xiang Liu | Penglei Sun | Shuyan Chen | Longhan Zhang | Peijie Dong | Huajie You | Yongqi Zhang | Chang Yan | Xiaowen Chu | Tong-yi Zhang
Findings of the Association for Computational Linguistics: EMNLP 2025
The rapid advancement of perovskite solar cells (PSCs) has led to an exponential growth in research publications, creating an urgent need for efficient knowledge management and reasoning systems in this domain. We present a comprehensive knowledge-enhanced system for PSCs that integrates three key components. First, we develop Perovskite-KG, a domain-specific knowledge graph constructed from 1,517 research papers, containing 23,789 entities and 22,272 relationships. Second, we create two complementary datasets: Perovskite-Chat, comprising 55,101 high-quality question-answer pairs generated through a novel multi-agent framework, and Perovskite-Reasoning, containing 2,217 carefully curated materials science problems. Third, we introduce two specialized large language models: Perovskite-Chat-LLM for domain-specific knowledge assistance and Perovskite-Reasoning-LLM for scientific reasoning tasks. Experimental results demonstrate that our system significantly outperforms existing models in both domain-specific knowledge retrieval and scientific reasoning tasks, providing researchers with effective tools for literature review, experimental design, and complex problem-solving in PSC research.
EssayJudge: A Multi-Granular Benchmark for Assessing Automated Essay Scoring Capabilities of Multimodal Large Language Models
Jiamin Su | Yibo Yan | Fangteng Fu | Zhang Han | Jingheng Ye | Xiang Liu | Jiahao Huo | Huiyu Zhou | Xuming Hu
Findings of the Association for Computational Linguistics: ACL 2025
Jiamin Su | Yibo Yan | Fangteng Fu | Zhang Han | Jingheng Ye | Xiang Liu | Jiahao Huo | Huiyu Zhou | Xuming Hu
Findings of the Association for Computational Linguistics: ACL 2025
Automated Essay Scoring (AES) plays a crucial role in educational assessment by providing scalable and consistent evaluations of writing tasks. However, traditional AES systems face three major challenges: (i) reliance on handcrafted features that limit generalizability, (ii) difficulty in capturing fine-grained traits like coherence and argumentation, and (iii) inability to handle multimodal contexts. In the era of Multimodal Large Language Models (MLLMs), we propose EssayJudge, the first multimodal benchmark to evaluate AES capabilities across lexical-, sentence-, and discourse-level traits. By leveraging MLLMs’ strengths in trait-specific scoring and multimodal context understanding, EssayJudge aims to offer precise, context-rich evaluations without manual feature engineering, addressing longstanding AES limitations. Our experiments with 18 representative MLLMs reveal gaps in AES performance compared to human evaluation, particularly in discourse-level traits, highlighting the need for further advancements in MLLM-based AES research. Our dataset and code will be available upon acceptance.
2024
LPZero: Language Model Zero-cost Proxy Search from Zero
Peijie Dong | Lujun Li | Xiang Liu | Zhenheng Tang | Xuebo Liu | Qiang Wang | Xiaowen Chu
Findings of the Association for Computational Linguistics: EMNLP 2024
Peijie Dong | Lujun Li | Xiang Liu | Zhenheng Tang | Xuebo Liu | Qiang Wang | Xiaowen Chu
Findings of the Association for Computational Linguistics: EMNLP 2024
Despite the outstanding performance, Neural Architecture Search (NAS) is criticized for massive computation. Recently, Zero-shot NAS has emerged as a promising approach by exploiting Zero-cost (ZC) proxies, which markedly reduce computational demands. Despite this, existing ZC proxies heavily rely on expert knowledge and incur significant trial-and-error costs. Particularly in NLP tasks, most existing ZC proxies fail to surpass the performance of the naive baseline. To address these challenges, we introduce a novel framework, LPZero, which is the first to automatically design zero-cost (ZC) proxies for various tasks, achieving higher ranking consistency than human-designed proxies. Specifically, we model the ZC proxy as a symbolic equation and incorporate a unified proxy search space that encompasses existing ZC proxies, which are composed of a predefined set of mathematical symbols. To heuristically search for the best ZC proxy, LPZero incorporates genetic programming to find the optimal symbolic composition. We propose a Predictive-Pruning Strategy (PPS), which preemptively eliminates unpromising proxies, thereby mitigating the risk of proxy degradation. Extensive experiments on FlexiBERT, GPT-2, and LLaMA-7B demonstrate LPZero’s superior ranking ability and performance on downstream tasks compared to current approaches.
LongGenBench: Long-context Generation Benchmark
Xiang Liu | Peijie Dong | Xuming Hu | Xiaowen Chu
Findings of the Association for Computational Linguistics: EMNLP 2024
Xiang Liu | Peijie Dong | Xuming Hu | Xiaowen Chu
Findings of the Association for Computational Linguistics: EMNLP 2024
Current long-context benchmarks primarily focus on retrieval-based tests, requiring Large Language Models (LLMs) to locate specific information within extensive input contexts, such as the needle-in-a-haystack (NIAH) benchmark. Long-context generation refers to the ability of a language model to generate coherent and contextually accurate text that spans across lengthy passages or documents. While recent studies show strong performance on NIAH and other retrieval-based long-context benchmarks, there is a significant lack of benchmarks for evaluating long-context generation capabilities. To bridge this gap and offer a comprehensive assessment, we introduce a synthetic benchmark, LongGenBench, which allows for flexible configurations of customized generation context lengths. LongGenBench advances beyond traditional benchmarks by redesigning the format of questions and necessitating that LLMs respond with a single, cohesive long-context answer. Upon extensive evaluation using LongGenBench, we observe that: (1) both API accessed and open source models exhibit performance degradation in long-context generation scenarios, ranging from 1.2% to 47.1%; (2) different series of LLMs exhibit varying trends of performance degradation, with the Gemini-1.5-Flash model showing the least degradation among API accessed models, and the Qwen2 series exhibiting the least degradation in LongGenBench among open source models.
Plum: Prompt Learning using Metaheuristics
Rui Pan | Shuo Xing | Shizhe Diao | Wenhe Sun | Xiang Liu | KaShun Shum | Jipeng Zhang | Renjie Pi | Tong Zhang
Findings of the Association for Computational Linguistics: ACL 2024
Rui Pan | Shuo Xing | Shizhe Diao | Wenhe Sun | Xiang Liu | KaShun Shum | Jipeng Zhang | Renjie Pi | Tong Zhang
Findings of the Association for Computational Linguistics: ACL 2024
Since the emergence of large language models, prompt learning has become a popular method for optimizing and customizing these models. Special prompts, such as Chain-of-Thought, have even revealed previously unknown reasoning capabilities within these models. However, the progress of discovering effective prompts has been slow, driving a desire for general prompt optimization methods. Unfortunately, few existing prompt learning methods satisfy the criteria of being truly “general”, i.e., automatic, discrete, black-box, gradient-free, and interpretable all at once. In this paper, we introduce metaheuristics, a branch of discrete non-convex optimization methods with over 100 options, as a promising approach to prompt learning. Within our paradigm, we test six typical methods: hill climbing, simulated annealing, genetic algorithms with/without crossover, tabu search, and harmony search, demonstrating their effectiveness in white-box and black-box prompt learning. Furthermore, we show that these methods can be used to discover more human-understandable prompts that were previously unknown in both reasoning and image generation tasks, opening the door to a cornucopia of possibilities in prompt optimization.
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- Xiaowen Chu 5
- Xuming Hu 5
- Peijie Dong 4
- Zhenheng Tang 3
- Yibo Yan 3
- Bo Li 2
- Jiamin Su 2
- Qian Wang 2
- Huiyu Zhou 2
- Haolan Chen 1
- Hong Chen 1
- Ronghao Chen 1
- Shuyan Chen 1
- Yuanlin Chu 1
- Shizhe Diao 1
- Keyan Ding 1
- Qiqi Duan 1
- Yuxuan Fan 1
- Fangteng Fu 1
- Yubo Gao 1
- Zhuoran Gao 1
- Weidong Guo 1
- Zhang Han 1
- Xin He 1
- Sen Hu 1
- Jiahao Huo 1
- Kunfeng Lai 1
- Changlun Li 1
- Lujun Li 1
- Qi Li 1
- Xiang Li 1
- Yuanguo Lin 1
- Shuliang Liu 1
- Xuebo Liu 1
- Di Lu 1
- Yuyu Luo 1
- Jie Mao 1
- Yew-Soon Ong 1
- Qihua Pan 1
- Rui Pan 1
- Renjie Pi 1
- Jingya Shen 1
- KaShun Shum 1
- Penglei Sun 1
- Wenhe Sun 1
- Jing Tang 1
- Nan Tang 1
- Ivor Tsang 1
- Bo Wang 1
- Huacan Wang 1
- Qiang Wang 1
- Yizhou Wang 1
- Fanjunduo Wei 1
- Shuo Xing 1
- Yu Xu 1
- Chang Yan 1
- Jingheng Ye 1
- Huajie You 1
- Jinhui Yuan 1
- Han Zhang 1
- Jipeng Zhang 1
- Linfeng Zhang 1
- Longhan Zhang 1
- Tong Zhang 1
- Tong-yi Zhang 1
- Yongqi Zhang 1
- Kaiyong Zhao 1
- Tiancheng Zhao 1
- Xin Zou 1