activity
20222026
most citedA Systematic Survey of Automatic Prompt Optimization Techniques

14 citations · 46 across the 28 of their papers we have counts for

collaborators

28 papers

cs.CL2026

VerTox: Verifiable Reward-Guided Corpus Poisoning Against Neural Ranking Models

Zhiqi Huang, Vivek Datla, Zhichao Xu +3

Neural ranking models have become core components of modern information retrieval systems and important building blocks of AI systems such as retrieval-augmented generation (RAG) p…

cs.CL2026

Beyond Supervised Clarification: Input Rewriting with LLMs for Dialogue Discourse Parsing

Yiming Liu, Ziyue Zhang, Zhichao Xu +4

Rewriting inputs to improve frozen downstream models has become a common strategy in modern NLP pipelines. Prior work on incremental dialogue discourse parsing (DDP) shows that sup…

cs.CL2026

Defragmenting Language Models: An Interpretability-based Approach for Vocabulary Expansion

Maitrey Mehta, Nishant Subramani, Zhichao Xu +2

All languages are equal; when it comes to tokenization, some are more equal than others. Tokens are the hidden currency that dictate the cost and latency of access to contemporary…

cs.LG2025

TransactionGPT

Yingtong Dou, Zhimeng Jiang, Tianyi Zhang +26

We present TransactionGPT (TGPT), a foundation model for consumer transaction data within one of the world's largest payment networks. TGPT is designed to understand and generate t…

cs.CL2025

Reinforcement Mid-Training

Yijun Tian, Shaoyu Chen, Zhichao Xu +4

The development of state-of-the-art large language models is commonly understood as a two-stage process involving pre-training and post-training. We point out the need for an addit…

cs.IR2025

ConvMix: A Mixed-Criteria Data Augmentation Framework for Conversational Dense Retrieval

Fengran Mo, Jinghan Zhang, Yuchen Hui +4

Conversational search aims to satisfy users' complex information needs via multiple-turn interactions. The key challenge lies in revealing real users' search intent from the contex…

cs.CL2025

Distillation versus Contrastive Learning: How to Train Your Rerankers

Zhichao Xu, Zhiqi Huang, Shengyao Zhuang +1

Training effective text rerankers is crucial for information retrieval. Two strategies are widely used: contrastive learning (optimizing directly on ground-truth labels) and knowle…

cs.CL2025★ 1 cited

Found in Translation: Measuring Multilingual LLM Consistency as Simple as Translate then Evaluate

Ashim Gupta, Maitrey Mehta, Zhichao Xu +1

Large language models (LLMs) provide detailed and impressive responses to queries in English. However, are they really consistent at responding to the same query in other languages…

cs.CL2025★ 2 cited

SLOT: Structuring the Output of Large Language Models

Darren Yow-Bang Wang, Zhengyuan Shen, Soumya Smruti Mishra +3

Structured outputs are essential for large language models (LLMs) in critical applications like agents and information extraction. Despite their capabilities, LLMs often generate o…

cs.CL2025★ 14 cited

A Systematic Survey of Automatic Prompt Optimization Techniques

Kiran Ramnath, Kang Zhou, Sheng Guan +18

Since the advent of large language models (LLMs), prompt engineering has been a crucial step for eliciting desired responses for various Natural Language Processing (NLP) tasks. Ho…

cs.IR2025★ 1 cited

CSPLADE: Learned Sparse Retrieval with Causal Language Models

Zhichao Xu, Aosong Feng, Yijun Tian +2

In recent years, dense retrieval has been the focus of information retrieval (IR) research. While effective, dense retrieval produces uninterpretable dense vectors, and suffers fro…

cs.IR2025★ 1 cited

A Survey of Model Architectures in Information Retrieval

Zhichao Xu, Fengran Mo, Zhiqi Huang +5

The period from 2019 to the present marks one of the most significant paradigm shifts in information retrieval (IR) and natural language processing (NLP), culminating in the emerge…

cs.CL2024★ 1 cited

MAIN-RAG: Multi-Agent Filtering Retrieval-Augmented Generation

Chia-Yuan Chang, Zhimeng Jiang, Vineeth Rakesh +8

Large Language Models (LLMs) are becoming essential tools for various natural language processing tasks but often suffer from generating outdated or incorrect information. Retrieva…

cs.CL2024

State Space Models are Strong Text Rerankers

Zhichao Xu, Jinghua Yan, Ashim Gupta +1

Transformers dominate NLP and IR; but their inference inefficiencies and challenges in extrapolating to longer contexts have sparked interest in alternative model architectures. Am…

cs.CL2024

Beyond Perplexity: Multi-dimensional Safety Evaluation of LLM Compression

Zhichao Xu, Ashim Gupta, Tao Li +2

Increasingly, model compression techniques enable large language models (LLMs) to be deployed in real-world applications. As a result of this momentum towards local deployment, com…

cs.IR2024★ 1 cited

RankMamba: Benchmarking Mamba's Document Ranking Performance in the Era of Transformers

Zhichao Xu

Transformer structure has achieved great success in multiple applied machine learning communities, such as natural language processing (NLP), computer vision (CV) and information r…

cs.CL2024★ 1 cited

In-Context Example Ordering Guided by Label Distributions

Zhichao Xu, Daniel Cohen, Bei Wang +1

By allowing models to predict without task-specific training, in-context learning (ICL) with pretrained LLMs has enormous potential in NLP. However, a number of problems persist in…

cs.CL2024★ 2 cited

Multi-dimensional Evaluation of Empathetic Dialog Responses

Zhichao Xu, Jiepu Jiang

Empathy is critical for effective and satisfactory conversational communication. Prior efforts to measure conversational empathy mostly focus on expressed communicative intents --…

cs.CL2023

Context-aware Decoding Reduces Hallucination in Query-focused Summarization

Zhichao Xu

Query-focused summarization (QFS) aims to provide a summary of a single document/multi documents that can satisfy the information needs of a given query. It is useful for various r…

cs.IR2023★ 4 cited

FARA: Future-aware Ranking Algorithm for Fairness Optimization

Tao Yang, Zhichao Xu, Zhenduo Wang +1

Ranking systems are the key components of modern Information Retrieval (IR) applications, such as search engines and recommender systems. Besides the ranking relevance to users, th…

cs.IR2023

A Lightweight Constrained Generation Alternative for Query-focused Summarization

Zhichao Xu, Daniel Cohen

Query-focused summarization (QFS) aims to provide a summary of a document that satisfies information need of a given query and is useful in various IR applications, such as abstrac…

cs.IR2023

Reward-free Policy Imitation Learning for Conversational Search

Zhenduo Wang, Zhichao Xu, Qingyao Ai

Existing conversational search studies mainly focused on asking better clarifying questions and/or improving search result quality. These works aim at retrieving better responses a…

cs.IR2023★ 3 cited

An In-depth Investigation of User Response Simulation for Conversational Search

Zhenduo Wang, Zhichao Xu, Qingyao Ai +1

Conversational search has seen increased recent attention in both the IR and NLP communities. It seeks to clarify and solve users' search needs through multi-turn natural language…

cs.IR2023

Counterfactual Editing for Search Result Explanation

Zhichao Xu, Hemank Lamba, Qingyao Ai +2

Search Result Explanation (SeRE) aims to improve search sessions' effectiveness and efficiency by helping users interpret documents' relevance. Existing works mostly focus on factu…