Email: [email protected] / [email protected]
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[Actively searching for positions in Texas]

I am a Visiting Assistant Professor in the Department of Statistics at University of California, Santa Cruz (UCSC). I obtained a Ph.D. in Statistics at University of California, Los Angeles (UCLA) in June 2024, under the supervision of Prof. Oscar Hernan Madrid Padilla.

My research focuses on developing realistic models and the associated inference and learning algorithms for multi-modal data to allow useful abstraction, generation, and detection. Extracting meaningful representations from data (abstraction) can help devise powerful models that produce valid knowledge in a real-world setting (generation), while identifying anomalies when certain criteria are violated (detection).

My research has also been advised by Prof. Mark S. Handcock and Prof. Ying Nian Wu at UCLA, Prof. Robert B. Lund, Prof. Rebecca Killick, Prof. James D. Wilson during my current position at UCSC, and many other amazing collaborators.

My research interests are

• Generative Models
• Representation Learning
• Graph Inference
• Anomaly Detection
• Empirical Bayes Methodology
• Optimization & Machine Learning

Previously, I have interned at Amazon and Cisco. I received a B.S. in Statistics and a B.A. in Economics at UCLA.

Publications

Published papers

1. Change Point Localization and Inference in Dynamic Multilayer Networks
   F. Wang, K. Ritscher, Yik Lun Kei, X. Ma, O.H. Madrid Padilla
   International Conference on Learning Representations (ICLR) 2026
   PDF

2. Change Point Detection on A Separable Model for Dynamic Networks
   Yik Lun Kei*, H. Li*, Y. Chen, O.H. Madrid Padilla
   Transactions on Machine Learning Research (TMLR) 2025
   PDF, Video, library(CPDstergm)
   Funded by NSF DMS-2015489

3. Change Point Detection in Dynamic Graphs with Decoder-only Latent Space Model
   Yik Lun Kei, J. Li, H. Li, Y. Chen, O.H. Madrid Padilla
   Transactions on Machine Learning Research (TMLR) 2025
   PDF, Video

4. A Partially Separable Model for Dynamic Valued Networks
   Yik Lun Kei, Y. Chen, O.H. Madrid Padilla
   Computational Statistics & Data Analysis 2023
   PDF

5. YouRefIt: Embodied Reference Understanding with Language and Gesture
   Y. Chen, Q. Li, D. Kong, Yik Lun Kei, S. Zhu, T. Gao, Y. Zhu, S. Huang
   The IEEE International Conference on Computer Vision (ICCV) 2021 (Oral)
   PDF

Preprints

1. Decoder-only Clustering in Graphs with Dynamic Attributes
   Yik Lun Kei, O.H. Madrid Padilla, R. Killick, J. Wilson, X. Chen, R. Lund
   Under Review
   PDF

2. Confidence Interval Construction and Conditional Variance Estimation with Dense ReLU Networks
   C.M. Madrid Padilla*, O.H. Madrid Padilla*, Yik Lun Kei, Z. Zhang, Y. Chen
   Under Review
   PDF

In Progress

1. Clustering Auto-regressive Models on Weighted Graphs
   Yik Lun Kei, O.H. Madrid Padilla, R. Killick, J. Wilson, X. Chen, R. Lund
   2026+

Others

1. Online Multi-robot Deadlock Prediction with Conditional Variational Auto-Encoder for Sequences
   Yik Lun Kei, M. Zhang, C. Stolz, A. Aroor, Y. Zhang, Y. Gao
   Amazon Robotics Science Summit

* denotes equal contribution

Teaching

STAT 132: Classical and Bayesian Inference
Lecture videos (Spring 2025)
Lecture videos (Fall 2024)

STAT 266A: Data Visualization and Statistical Programming in R

STAT 131: Introduction to Probability Theory

STAT 80A: Gambling and Gaming

STAT 280B: Seminars in Statistics

Industry Research Experience

Cisco
Software Engineer Intern (2024)

Amazon Robotics
Data Scientist Intern (2023)

UCLA Health
Senior Data Analyst (2017-2019)

Software

library(CPDstergm)
Github

• An R package to detect multiple change points in time series of graphs, using Separable Temporal Exponential-family Random Graph Model (STERGM). The optimization problem with Group Fused Lasso regularization on the model parameters is solved by Alternating Direction Method of Multipliers (ADMM).

library(GraphClustAR)

• In Progress

Talks

Department of Statistics, University of California, Santa Cruz (April 2024)

Awards

UCLA Graduate Fellowship (2021-2023)
UCLA Summer Mentored Research Fellowship (2022)

Services

Journal Reviewer
NSF Grant Reviewer
Master Thesis Committee
Graudate Student Mentor