Lei Zan (昝磊)

I study how machines can identify structure in complex data, reason with it, and remain useful when the world changes.

My work connects causal discovery, time-series modelling, root-cause analysis, and foundation-model agents. I care about methods that are both scientifically grounded and ready to work on real systems.

Bio

I am an AI research engineer with a PhD in machine learning and experience spanning both academic and industrial research.

During my industrial PhD with EasyVista and Université Grenoble Alpes, I developed causal discovery and root-cause analysis methods for heterogeneous operational data. The resulting methods were integrated into EV Observe, and part of the work was contributed to the open-source Tigramite library.

At Huawei Noah's Ark AI Lab, I extended this research to foundation models: mathematical reasoning agents, causal diagnosis for telecommunications networks, and synthetic observational and interventional data for time-series pre-training. Across these projects, my recurring question is how structural knowledge can make an AI system more reliable, interpretable, and efficient.

Publications

2026

AAAI

CAMA: Enhancing Mathematical Reasoning in Large Language Models with Causal Knowledge

Lei Zan, Keli Zhang, Ruichu Cai, and Lujia Pan

Builds a causal graph of reusable problem-solving knowledge and retrieves relevant strategies to guide mathematical reasoning.

Preprint

EvoCause: Towards Causal Graph Evolution with Large Language Models for Root Cause Analysis

Lei Zan, Keli Zhang, Shifeng Xie, Jiale Zheng, Zehao Xiao, Zhiwei Dong, Ke Zhang, Ruichu Cai, Malik Tiomoko, and Lujia Pan

Uses language-model guidance to refine causal graphs and improve root-cause identification in complex event systems.

Preprint

Post-Training in Time Series Foundation Models

Shifeng Xie, Ambroise Odonnat, Zehao Xiao, Lei Zan, Malik Tiomoko, Lujia Pan, Themis Palpanas, Boris N. Oreshkin, Chenghao Liu, and Keli Zhang

Studies a unified post-training framework for adapting time-series foundation models across forecasting and classification tasks.

2024

CIKM

On the Fly Detection of Root Causes from Observed Data with Application to IT Systems

Lei Zan, Charles K. Assaad, Emilie Devijver, Eric Gaussier, and Ali Ait-Bachir

Introduces an efficient root-cause method for threshold-based IT systems without requiring a known causal graph.

CIKM

Causal Discovery from Heterogeneous Multivariate Time Series

Lei Zan

Presents the doctoral research programme on learning causal structure from heterogeneous operational time series.

2023

AISTATS

Root Cause Identification for Collective Anomalies in Time Series Given an Acyclic Summary Causal Graph with Loops

Charles K. Assaad, Imad Ez-Zejjari, and Lei Zan

Develops EasyRCA to identify the causes of collective anomalies using causal structure and normal and abnormal observations.

Preprint

Case Studies of Causal Discovery from IT Monitoring Time Series

Ali Ait-Bachir, Charles K. Assaad, Christophe de Bignicourt, Emilie Devijver, Simon Ferreira, Eric Gaussier, Hosein Mohanna, and Lei Zan

Examines the practical constraints and evaluation questions that arise when causal discovery meets operational monitoring data.

2022

Entropy

A Conditional Mutual Information Estimator for Mixed Data and an Associated Conditional Independence Test

Lei Zan, Anouar Meynaoui, Charles K. Assaad, Emilie Devijver, and Eric Gaussier

Proposes an estimator and independence test for datasets that mix quantitative and qualitative variables.

Awards

2026

Spark Award
Huawei Digital Communications Wireless Department

2025

Grand Prize
Huawei France Tech Arena Coding Competition

2024

Invited Speaker
Young Statisticians and Probabilists Day, French Statistical Society