CV
My curriculum vitae. Click the PDF icon above to download a copy.
Contact Information
| Name | Xiangjun (Ethan) Fu |
| Professional Title | Graduate Researcher, University of Pennsylvania |
| xjf@seas.upenn.edu | |
| Phone | (858) 539-5848 |
| Location | Philadelphia, PA |
| Website | https://ethanfusion03.github.io |
Professional Summary
M.S.E. student in Computer & Information Science at the University of Pennsylvania. I work on latent reasoning for large language models — continuous chain-of-thought via normalizing flows — and previously on benchmarking LLMs as semantic encoders for retrieval and recommendation.
Experience
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2025 - present Philadelphia, PA
Graduate Researcher
GMLR Lab, University of Pennsylvania
Advised by Prof. Jiatao Gu.
- Designing a continuous latent chain-of-thought reasoning pipeline on a Qwen3-8B backbone that operates in a lower-dimensional space while preserving semantic structure.
- Fine-tuning an LLM-based VAE encoder to provide semantic guidance for latent thinking-token generation; using normalizing flows to autoregressively generate thinking tokens under an MSE objective against VAE-encoded latents.
- Computing step-wise log-likelihoods to enable reinforcement learning over reasoning trajectories, with evaluation protocols for trajectory selection.
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2024 - 2025 San Diego, CA
Undergraduate Researcher
McAuley Lab, UC San Diego
Advised by Prof. Julian McAuley and Yupeng Hou.
- Built an evaluation framework for benchmarking LLM text embeddings in retrieval and recommendation, including a public Amazon dataset with 2M+ training and 250K+ test instances.
- Benchmarked embeddings from SimCSE, E5-Mistral-7B, text-embedding-3-large, Qwen-7B, Gemini, and OpenAI across collaborative filtering, sequential recommendation, and product search; co-first-authored the resulting ACL 2026 paper.
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2023 - 2024 San Diego, CA
Undergraduate Researcher
Shang Data Lab, UC San Diego
Advised by Prof. Jingbo Shang and Letian Peng.
- Refined weakly supervised text classification, reaching 93% peak accuracy on AG News (vs. 78% baseline) via KL-divergence matching between token-level text and class-prompt distributions.
- Implemented the framework in PyTorch with BERT, RoBERTa, and Gemma across AG News and Rotten Tomatoes.
Education
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2025 - 2027 Philadelphia, PA
M.S.E. in Computer & Information Science
University of Pennsylvania
- GPA: 3.95 / 4.0
- Relevant coursework: Statistical NLP, Deep Learning, Deep Generative Modeling, Reinforcement Learning, Machine Learning, Recommender Systems & Web Mining, Probability & Statistics
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2021 - 2025 San Diego, CA
B.S. in Mathematics–Computer Science
University of California, San Diego
- GPA: 3.9 / 4.0 · Provost Honors
Publications
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2026 Bridging Language and Items for Retrieval and Recommendation: Benchmarking LLMs as Semantic Encoders
ACL 2026 Main Conference (Oral)
Yupeng Hou†, Jiacheng Li†, Xiangjun Fu†, Zhankui He, An Yan, Xiusi Chen, Julian McAuley. († equal contribution)
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2026 Latent Reasoning with Normalizing Flows
COLM 2026 Workshop on Efficient Reasoning
Guancheng Tu†, Xiangjun Fu†, Suhao Yu, Yao Tang, Haoqiang Kang, Lianhui Qin, Yizhe Zhang, Jiatao Gu. († equal contribution, order by coin toss)
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2025 Larger Hausdorff Dimension in Scanning Pattern Facilitates Mamba-Based Methods in Low-Light Image Enhancement
Under review · arXiv:2510.26001
Xinhua Wang, Xiangjun Fu, Caibo Feng, Chunxiao Liu.
Teaching
- Supplemental Instruction Leader, Academic Achievement Hub, UC San Diego (2024–2025). Led weekly workshops for 50+ students in Physics and Calculus (~20 hrs/week), translating complex technical material into accessible, interactive lessons; iterated lesson design from student and faculty feedback and provided one-on-one mentorship.
Academic Service
- Reviewer: EMNLP 2026 (ACL Rolling Review, May cycle), NeurIPS 2026.
Skills
Programming: Python, C/C++, Java, SQL, Bash
ML & NLP: PyTorch, Hugging Face Transformers, LLM fine-tuning (LoRA, full fine-tuning), normalizing flows, flow matching/diffusion, VAEs, embedding models (BERT, RoBERTa, Mistral, Qwen), OpenAI / Gemini / Claude APIs
Tools: NumPy, Pandas, Matplotlib, Jupyter, Git, Linux, Vim, gdb, SLURM / HPC clusters, conda
Languages
English : Fluent
Mandarin : Fluent
Cantonese : Conversational
Spanish : Conversational