Explicit and Implicit Reasoning
I study how language models reason and solve problems, spanning explicit reasoning steps, implicit representations, and the use of memory.
Georgia Institute of Technology · GTISC Lab · Atlanta
I am a Computer Science Ph.D. student at Georgia Tech, advised by Prof. Wenke Lee in the GTISC Lab. My research centers on LLM post-training and agentic AI, with particular interests in reasoning, diffusion language models, and systems that make language models more useful in interactive environments.
Before joining the Ph.D. program, I earned my B.Eng. in Communication Engineering (Artificial Intelligence Track) from Wuhan University.
I study how language models reason and solve problems, spanning explicit reasoning steps, implicit representations, and the use of memory.
I explore efficient and scalable language models, balancing computational cost, model capabilities, and the ability to handle long contexts.
I study language model agents that reason, act, and interact with their environments, aiming to make them more capable and reliable across tasks.
Industry researchLanguage models
2026
To preserve information between denoising steps, MetaState trains recurrent working-memory modules around a frozen diffusion language model, improving mathematical reasoning and code generation.
@misc{metastate2026,
title = {MetaState: Persistent Working Memory Enhances Reasoning in Discrete Diffusion Language Models},
author = {Kejing Xia and Mingzhe Li and Lixuan Wei and Zhenbang Du and Xiangchi Yuan and Dachuan Shi and Qirui Jin and Wenke Lee},
year = {2026},
eprint = {2603.01331},
archivePrefix = {arXiv},
primaryClass = {cs.CL},
url = {https://arxiv.org/abs/2603.01331}
}
To reduce redundant diffusion steps, R²-dLLM combines training-free spatial and temporal decoding rules with redundancy-aware supervised fine-tuning, improving the trade-off between computation and generation quality.
@misc{r2dllm2026,
title = {{R$^2$-dLLM}: Accelerating Diffusion Large Language Models via Spatio-Temporal Redundancy Reduction},
author = {Zhenbang Du and Kejing Xia and Xinrui Zhong and Yonggan Fu and Nicolai Oswald and Binfei Ji and Brucek Khailany and Pavlo Molchanov and Yingyan (Celine) Lin},
year = {2026},
eprint = {2604.18995},
archivePrefix = {arXiv},
primaryClass = {cs.CL},
url = {https://arxiv.org/abs/2604.18995}
}
2025
To reconstruct urban scenes without LiDAR, D²GS jointly refines dense depth and Gaussian geometry using diffusion priors, with progressive point pruning and road-specific geometric constraints.
@inproceedings{NEURIPS2025_524ff06d,
author = {Xia, Kejing and Jia, Jidong and Jin, Ke and BAI, Yucai and Sun, Li and Tao, Dacheng and Zhang, Youjian},
booktitle = {Advances in Neural Information Processing Systems},
doi = {10.52202/085713-1905},
editor = {D. Belgrave and C. Zhang and H. Lin and R. Pascanu and P. Koniusz and M. Ghassemi and N. Chen},
pages = {56899--56927},
publisher = {Curran Associates, Inc.},
title = {D\^{}2GS: Dense Depth Regularization for LiDAR-free Urban Scene Reconstruction},
url = {https://proceedings.neurips.cc/paper_files/paper/2025/file/524ff06d5375d76e93d8490e654a81bf-Paper-Conference.pdf},
volume = {38, Main Conference},
year = {2025}
}
To recover interpretable prompts from generated images, EDITOR combines caption-based initialization, latent-space optimization, and embedding-to-text conversion, balancing visual reconstruction with readable textual descriptions.
@misc{editor2025,
title = {EDITOR: Effective and Interpretable Prompt Inversion for Text-to-Image Diffusion Models},
author = {Mingzhe Li and Kejing Xia and Gehao Zhang and Zhenting Wang and Guanhong Tao and Siqi Pan and Juan Zhai and Shiqing Ma},
year = {2025},
eprint = {2506.03067},
archivePrefix = {arXiv},
primaryClass = {cs.CV},
url = {https://arxiv.org/abs/2506.03067}
}
To counter memory decay at long context lengths, LongMamba identifies global state channels and filters unimportant tokens, enlarging receptive fields without additional training.
@inproceedings{ICLR2025_ab5d50d2,
author = {Ye, Zhifan and Xia, Kejing and Fu, Yonggan and Dong, Xin and Hong, Jihoon and Yuan, Xiangchi and Diao, Shizhe and Kautz, Jan and Molchanov, Pavlo and Lin, Yingyan Celine},
booktitle = {International Conference on Learning Representations},
editor = {Y. Yue and A. Garg and N. Peng and F. Sha and R. Yu},
pages = {68486--68504},
title = {LongMamba: Enhancing Mamba\textquotesingle s Long-Context Capabilities via Training-Free Receptive Field Enlargement},
url = {https://proceedings.iclr.cc/paper_files/paper/2025/file/ab5d50d269e52f8eed497062311ff173-Paper-Conference.pdf},
volume = {2025},
year = {2025}
}
By examining attention patterns in state space models, LAMB guides token filtering to preserve critical information, strengthening long-context understanding in pure and hybrid models without training.
@inproceedings{ye-etal-2025-lamb,
title = "{LAMB}: A Training-Free Method to Enhance the Long-Context Understanding of {SSM}s via Attention-Guided Token Filtering",
author = "Ye, Zhifan and
Wang, Zheng and
Xia, Kejing and
Hong, Jihoon and
Li, Leshu and
Whalen, Lexington and
Wan, Cheng and
Fu, Yonggan and
Lin, Yingyan Celine and
Kundu, Souvik",
editor = "Che, Wanxiang and
Nabende, Joyce and
Shutova, Ekaterina and
Pilehvar, Mohammad Taher",
booktitle = "Proceedings of the 63rd Annual Meeting of the Association for Computational Linguistics (Volume 2: Short Papers)",
month = jul,
year = "2025",
address = "Vienna, Austria",
publisher = "Association for Computational Linguistics",
url = "https://aclanthology.org/2025.acl-short.96/",
doi = "10.18653/v1/2025.acl-short.96",
pages = "1200--1209",
ISBN = "979-8-89176-252-7"
}
Ph.D. student
Jan. 2026 – Present
Developed persistent working-memory augmentation for reasoning across diffusion steps.
Undergraduate to Ph.D. student
May 2024 – Feb. 2026
Studied efficient diffusion decoding and long-context memory retention in state space models, including redundancy-aware decoding, soft token interpolation, and token filtering.
Undergraduate student
Oct. 2023 – Apr. 2024
Developed an event-and-RGB pipeline for BRS-E²NeRF, jointly addressing rolling-shutter distortion and motion blur for sharp 3D reconstruction and novel-view synthesis.
2023 – 2024
Research on event-based human behavior analysis using spatio-temporal transformers, presented at the IJCAI 2024 MiGA Workshop.
Research Intern
May 2026 – Aug. 2026
Native Action Merging for Efficient Computer-Use Agents: an execution-batching framework that merges consecutive GUI actions when intermediate observations are unnecessary, reducing repeated visual processing and model deliberation.
Research Intern
Jul. 2024 – May 2025
Co-optimized diffusion-based depth generation and 3D Gaussian Splatting for LiDAR-free urban reconstruction. Worked on road-specific geometric constraints and benchmarking on Waymo.
Aug. 2025 – Present
Ph.D. in Computer Science · In progress
Sept. 2021 – Jun. 2025
B.Eng. in Communication Engineering (Artificial Intelligence Track)
I studied at the No. 1 Middle School Affiliated to Central China Normal University.