Yun-Yun (Alice) Tsai

§ Welcome to my personal website §

About Me

Portrait of Yun-Yun (Alice) Tsai

Hi human or agent, nice to meet you!

I'm Yun-Yun (Alice) Tsai (蔡昀芸), a sixth year (final-year) Ph.D. in the Department of Computer Science at Columbia University, advised by Professor Junfeng Yang.

My research focuses on machine learning robustness in vision + language domain, test-time adaptation, LLM safety, and auto-evaluation for agentic systems. My goal is to design trustworthy and reliable foundation models and AI agent frameworks.

I received Bachelor's and Master's degrees in computer science, both from National Tsing Hua University (NTHU), Taiwan. Previously, I was advised by Professor Tsung-Yi Ho and Dr. Pin-Yu Chen from IBM Research Trusted AI group.

Misc:
- I am looking for strong motivated students for Research collaboration, working on broad AI security and agent auto-evaluation problems. I mentor both master and undergraduate students. If you know how to build fundamental AI algos or models, we should talk. Welcome to send me a human-written email to yt2781@columbia.edu.
- I am currently on the job market! I am looking for faculty positions in AI/ML track for next Fall, 2027, and also open to industry research scientist roles.

News

  • [2025 May] Started research scientist intern at Meta SuperIntellience Labs @ Bellevue, WA.
  • [2024 May] Started research scientist intern at Meta GenAI Team @ New York, NY.
  • [2024 April] I passed my Ph.D. candidacy exam on April 24 2024. Thank to my committee members Prof. Richard Zemel, Prof. Carl Vondrick, and Prof. Junfeng Yang. (Slides)
  • [2024 Feb] One main conf. paper + two workshop papers are accepted by CVPR 2024. See you in Seattle!
  • [2023 Sep] One paper is accepted by NeurIPS 2023 @ New Orleans.
  • [2023 May] Started applied scientist internship at Amazon Astro Team @ Bellevue Washington.
  • [2023 Mar] Two papers are accepted by CVPR 2023 @ Vancouver.

What I Enjoy

Research

I work on Security in Artificial Intelligence: making machine learning algorithms and computer systems more trustworthy, secure, and robust — from adversarial robustness and test-time defenses to detecting AI-generated media.

To my papers

Music

I love music and have played the piano and viola for over 20 years. I was the 1st chair viola of Tsing Hua Symphony Orchestra for 4 years, and am a violist of the Columbia University Orchestra, performing at Lincoln Center's Alice Tully Hall.

Others

Snapshots beyond papers: internship experiences at Microsoft, visiting research at the University of Florida, conference travels, invited talks, volunteering, and team leadership.

To my photos

Professional Experience

§Research & Working Experience

§ Honors, Awards, and Grants

June 2024
Awarded the 2024 CVPR's Travel Grant
Nov. 2023
Awarded the 2023 NeurIPS's scholar award
June 2023
Awarded the 2023 CVPR's scholar award
Sep. 2021
PhD Dean’s Fellowship, Fu Foundation School of Engineering and Applied Sciences, Columbia University.
Aug.2020
Best Presenter, Blackhat Award Forum in CyberSec, Taiwan, 2020.

§ Service

Paper Review
ICCV '25, CVPR '23 '24 '25, NeurIPS '23, IEEE Access, KDD '21, ICLR '21, AAAI '21
Teaching Assistant
Computer Vision II, Engineering Software-as-a-Service, Fundamental of Formal Language, Very-Large-Scale Integration

§ Invited Speech

Dec.7.2025
I was invited to give a talk at AI Governance course, taught by Professor Lake Dai, at Carnegie Mellon University Silicon Valley.
Jan.7.2025
I was invited to give a talk about"Exploring Safety of Machine Learning Models and Generative AI" at the Department of Electrical Engineering, National Taiwan University (NTU), hosted by Professor Shao-Hua Sun.
Dec.7.2024
I was invited to give a talk at Young Women Star session at Taiwanese Association of Aritificial Intelligence (TAAI) 2024.
Dec.5.2020
I was invited to give a talk about my ICML'20 paper at Taiwanese Association of Aritificial Intelligence (TAAI) 2020.
Aug.12.2020
I was invited to give a talk about "CloudLeak: DNN Model Extractions from Commercial MLaaS Platforms" at CyberSec 2020 Blackhat Awarded Forum, Taipei.

Publications

§Conference and Workshop Papers

  1. WebUIProof benchmark examples

    WebUIProof: Benchmarking WebUI Code Generators with UI-Agent Execution Harness

    Yun-Yun Tsai, Yuning Mao, Shiqi Wang, Junfeng Yang, Sinong Wang

    arXiv 2026 paper

    WebUIProof is an execution-oriented benchmark for evaluating WebUI code generation beyond visual appearance or build success. It provides structured UI specifications and dense, executable interaction tests that verify whether generated websites actually behave correctly under user actions, covering both general WebUIs and interactive 3D simulations.

  2. RAFP fingerprinting framework

    RAFP: Identifying LLM Lineages via Rare-Region Fingerprints

    Yun-Yun Tsai, Jia-Hao Liang, Chuan Guo, Junfeng Yang, Laurens van der Maaten

    arXiv 2025 paper

    RAFP is a black-box fingerprinting framework for verifying LLM lineage and ownership through carefully optimized prompt–response pairs. It constructs rare, model-specific behavioral fingerprints that remain detectable even after common model modifications such as fine-tuning, LoRA, quantization, system-prompt changes, and different decoding settings, enabling robust post-deployment model provenance verification without access to model weights.

  3. ARQ agentic query refinement loop

    ARQ: Agentic CodeQL Query Refinement for C/C++ Vulnerability Detection

    Chunyi Wang, Yunfei Ke, Junfeng Yang, Yun-Yun Tsai, Penghui Li

    arXiv 2026 paper

    ARQ is an agentic framework that automatically refines C/C++ CodeQL vulnerability-detection queries: it synthesizes near-identical witness programs, checks the query’s verdict against execution oracles to expose false positives and false negatives, and iteratively repairs the query — no labeled data or vulnerability-specific templates needed.

  4. CAPTCHA-X framework

    Reasoning under Vision: Understanding Visual-Spatial Cognition in Vision-Language Models for CAPTCHA

    Jincen Song, Luke Tenyi Wang, Yun-Yun Tsai, Penghui Li, Junfeng Yang

    AACL 2026 Findings of the Association for Computational Linguistics paper

    We study how vision-language models perform visual-spatial reasoning through CAPTCHA-style tasks. It uses controlled visual challenges to probe whether models can accurately perceive objects, understand spatial relationships, and reason over visual layouts, revealing where current VLMs succeed and where their visual reasoning still breaks down.

  5. REVEAL framework

    REVEAL: Robust Evolution of Vision-Language Models for Explainable AI-Video Detection

    Yun-Yun Tsai, Qingyuan Liu, Ruijian Zha, Victoria Li, Pengyuan Shi, Chengzhi Mao, Junfeng Yang

    ICCV 2025 Workshop Knowledge-Intensive Multimodal Reasoning Workshop paper

    We propose an explainable AI-video detection framework that improves robustness by jointly leveraging visual evidence and vision-language reasoning. It helps distinguish real from AI-generated videos while producing interpretable explanations for its predictions, aiming to make detection more reliable across different generators and manipulation conditions.

  6. GDA framework

    GDA: Generalized Diffusion for Robust Test-time Adaptation

    Yun-Yun Tsai, Fu-Chen Chen, Albert Y. C. Chen, Junfeng Yang, Che-Chun Su, Min Sun, Cheng-Hao Kuo

    CVPR 2024 The IEEE / CVF Computer Vision and Pattern Recognition Conference paper

    GDA is a diffusion-driven test-time adaptation framework that improves model robustness under distribution shifts without retraining. It uses diffusion-based conditional generation together with entropy, style, and content objectives to adapt inputs at inference time, helping pretrained models recover performance on out-of-distribution data.

  7. Convolutional Visual Prompt framework

    Convolutional Visual Prompt for Robust Visual Perception

    Yun-Yun Tsai, Chengzhi Mao, Junfeng Yang

    NeurIPS 2023 37th Conference on Neural Information Processing Systems paper

    We propose CVP, a lightweight test-time adaptation method that learns convolutional input-space prompts to improve model robustness under distribution shift. By modifying visual inputs rather than updating the full model, it enables efficient deployment-time adaptation while preserving the pretrained model and improving performance on out-of-distribution data.

  8. Compositional adversarial attack framework

    Towards Compositional Adversarial Robustness: Generalizing Adversarial Training to Composite Semantic Perturbations

    Lei Hsiung, Yun-Yun Tsai, Pin-Yu Chen, Tsung-Yi Ho

    CVPR 2023 The IEEE / CVF Computer Vision and Pattern Recognition Conference paper

    Towards Compositional Adversarial Robustness extends adversarial training beyond single perturbation types to composite semantic attacks. It trains models to remain robust when multiple meaningful transformations are combined, improving generalization to more realistic and previously unseen adversarial perturbations.

  9. MAE-based attack detection and repair framework

    Test-time Defense against Adversarial Attacks: Detection and Reconstruction of Adversarial Examples via Masked Autoencoder

    Yun-Yun Tsai, Ju-Chin Chao, Albert Wen, Zhaoyuan Yang, Chengzhi Mao, Tapan Shah, Junfeng Yang

    CVPR 2023 Workshop AdvML Workshop paper

    We use a pretrained masked autoencoder (MAE) as a test-time defense: its reconstruction loss flags adversarial inputs at inference, and its latent features repair the image so the classifier predicts correctly — requiring no model retraining.

  10. CARBEN demo

    CARBEN: Composite Adversarial Robustness Benchmark

    Lei Hsiung, Yun-Yun Tsai, Pin-Yu Chen, Tsung-Yi Ho

    IJCAI 2022 International Joint Conference on Artificial Intelligence paper demo

    CARBEN is a benchmark of composite adversarial attacks that combine multiple semantic perturbations, for evaluating model robustness beyond standard single-type ℓ∞ attacks.

  11. Voice2Series framework

    Voice2Series: Reprogramming Acoustic Models for Time Series Classification

    Chao-Han Huck Yang, Yun-Yun Tsai, Pin-Yu Chen

    ICML 2021 International Conference on Machine Learning paper

    Voice2Series reprograms pretrained acoustic models for time-series classification by transforming non-audio time-series signals into representations that speech models can understand. It enables knowledge from large pretrained speech models to transfer to diverse time-series tasks, achieving strong classification performance with limited task-specific training.

  12. Black-box adversarial reprogramming framework

    Transfer Learning without Knowing, Reprogramming Black-box Machine Learning Model with Scarce Data and Limited Resources

    Yun-Yun Tsai, Pin-Yu Chen, Tsung-Yi Ho

    ICML 2020 International Conference on Machine Learning paper video slides code

    We introduce a black-box model reprogramming framework that repurposes pretrained machine learning models for new tasks without access to their architecture, parameters, or training data. It learns input/output transformations through model queries, enabling knowledge transfer from inaccessible models to substantially different target tasks.

  13. CloudLeak model extraction framework

    CloudLeak: Large-Scale Deep Learning Models Stealing Through Adversarial Examples

    Honggang Yu, Kaichen Yang, Teng Zhang, Yun-Yun Tsai, Tsung-Yi Ho, Yier Jin

    NDSS 2020 Network and Distributed System Security Symposium paper code

    We introduce an efficient black-box model-stealing attack against cloud ML services. It combines adversarial example generation, active learning, and transfer learning to selectively query informative samples near the victim model’s decision boundary, allowing an attacker to train a local substitute model with similar behavior using far fewer queries than prior extraction attacks.

  14. Vehicle sequence reordering illustration

    Vehicle Sequence Reordering with Cooperative Adaptive Cruise Control

    Ta-Wei Huang, Yun-Yun Tsai, Chung-Wei Lin, Tsung-Yi Ho

    DATE 2019 Design, Automation & Test in Europe Conference & Exhibition paper

    We study reordering the crossing sequence of connected vehicles with cooperative adaptive cruise control, showing that coordinating the order vehicles pass through intersections can reduce total delay and improve traffic throughput compared with first-come-first-served scheduling.

§Patents

  1. Pin-Yu Chen, Yun-Yun Tsai, Sijia Liu, Chia-Yu Chen, I-Hsin Chung, Tsung-Yi Ho. ”Transfer Learning With Machine Learning Systems”, U.S. Patent Application No: 17/029506, Application Date: Sept. 23, 2020.

  2. Pin-Yu Chen, I-Hsin Chung, Bo Wu, Chuang Gan, Lei Hsiung, Yun-Yun Tsai, Tsung-Yi Ho. ”Composite Adversarial Attack Model Training For Neural Networks”, U.S. Patent Application No: 18/331,211, Application Date: May 12, 2026.