Tianyi Zhang
Purdue
Other people with similar names: TianYi Zhang, Tianyi Zhang (British Columbia), Tianyi Zhang, Tianyi Zhang (Melbourne), Tianyi Zhang (UPenn)
Unverified author pages with similar names: Tianyi Zhang
2026
PV-SQL: Synergizing Database Probing and Rule-based Verification for Text-to-SQL Agents
Yuan Tian | Tianyi Zhang
Findings of the Association for Computational Linguistics: ACL 2026
Yuan Tian | Tianyi Zhang
Findings of the Association for Computational Linguistics: ACL 2026
Text-to-SQL systems often struggle with deep contextual understanding, particularly for complex queries with subtle requirements.We present **PV-SQL**, an agentic framework that addresses these failures through two complementary components: **P**robe and **V**erify. The *Probe* component iteratively generates probing queries to retrieve concrete records from the database, resolving ambiguities in value formats, column semantics, and inter-table relationships to build richer contextual understanding. The *Verify* component employs a rule-based method to extract verifiable conditions and construct an executable checklist, enabling iterative SQL refinement that effectively reduces missing constraints. Experiments on the BIRD benchmarks show that PV-SQL outperforms the best text-to-SQL baseline by 5% in execution accuracy and 20.8% in valid efficiency score while consuming fewer tokens.
Mango: Multi-Agent Web Navigation via Global-View Optimization
Weixi Tong | Yifeng Di | Tianyi Zhang
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Weixi Tong | Yifeng Di | Tianyi Zhang
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Existing web agents typically initiate exploration from the root URL, which is inefficient for complex websites with deep hierarchical structures. Without a global view of the website’s structure, agents frequently fall into navigation traps, explore irrelevant branches, or fail to reach target information within a limited budget. We propose Mango, a multi-agent web navigation method that leverages the website structure to dynamically determine optimal starting points. We formulate URL selection as a multi-armed bandit problem and employ Thompson Sampling to adaptively allocate the navigation budget across candidate URLs. Furthermore, we introduce an episodic memory component to store navigation history, enabling the agent to learn from previous attempts. Experiments on WebVoyager demonstrate that Mango achieves a success rate of 63.6% when using GPT-5-mini, outperforming the best baseline by 7.3%. Furthermore, on WebWalkerQA, Mango attains a 52.5% success rate, surpassing the best baseline by 26.8%. We also demonstrate the generalizability of Mango using both open-source and closed-source models as backbones. Our data and code are open-source and available at https://github.com/VichyTong/Mango.
2025
Active Layer-Contrastive Decoding Reduces Hallucination in Large Language Model Generation
Hongxiang Zhang | Hao Chen | Muhao Chen | Tianyi Zhang
Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing
Hongxiang Zhang | Hao Chen | Muhao Chen | Tianyi Zhang
Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing
Recent decoding methods improve the factuality of large language models (LLMs) by refining how the next token is selected during generation. These methods typically operate at the token level, leveraging internal representations to suppress superficial patterns. Nevertheless, LLMs remain prone to hallucinations, especially over longer contexts. In this paper, we propose Active Layer-Contrastive Decoding (ActLCD), a novel decoding strategy that actively decides when to apply contrasting layers during generation. By casting decoding as a sequential decision-making problem, ActLCD employs a reinforcement learning policy guided by a reward-aware classifier to optimize factuality beyond the token level. Our experiments demonstrate that ActLCD surpasses state-of-the-art methods across five benchmarks, showcasing its effectiveness in mitigating hallucinations in diverse generation scenarios.
2024
CodeJudge: Evaluating Code Generation with Large Language Models
Weixi Tong | Tianyi Zhang
Proceedings of the 2024 Conference on Empirical Methods in Natural Language Processing
Weixi Tong | Tianyi Zhang
Proceedings of the 2024 Conference on Empirical Methods in Natural Language Processing
Large Language Models (LLMs) have shown promising performance in code generation. However, how to reliably evaluate code generated by LLMs remains an unresolved problem. This paper presents CodeJudge, a code evaluation framework that leverages LLMs to evaluate the semantic correctness of generated code without the need for test cases. We investigate different ways to guide the LLM in performing “slow thinking” to arrive at an in-depth and reliable evaluation. We experimented with four LLMs as evaluators on four code generation datasets and five programming languages. The results show that CodeJudge significantly outperformed existing methods in most settings. Furthermore, compared with a SOTA GPT-3.5-based code evaluation method, CodeJudge achieved better results even when using a much smaller model, Llama-3-8B-Instruct. Our code and datasets are available on GitHub https://github.com/VichyTong/CodeJudge.