Michalis Titsias
Also known as Michalis K. Titsias
Michalis Titsias is a machine learning researcher at Google DeepMind whose work covers variational inference, sparse Gaussian processes, Monte Carlo sampling and gradient estimation. After studying computer science at the University of Ioannina, they earned a PhD at the University of Edinburgh in 2005 under Christopher Williams, and they held postdoctoral posts at the University of Oxford and the University of Manchester and an assistant professorship at the Athens University of Economics and Business. Early papers include a 2009 variational method for sparse Gaussian processes and the 2014 Doubly Stochastic Variational Bayes algorithm, written with Miguel Lázaro-Gredilla. In 2022, they coauthored Gradient Estimation with Discrete Stein Operators, a NeurIPS 2022 Outstanding Paper, and in 2024 they coauthored Simplified and Generalized Masked Diffusion for Discrete Data. They are a research scientist at Google DeepMind in London.
- Now at
- Google DeepMind
- Badges
Timeline
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2005
A PhD at Edinburgh
After studying computer science at the University of Ioannina in Greece, they complete a PhD at the University of Edinburgh. The thesis, Unsupervised Learning of Multiple Objects in Images, is advised by Christopher Williams at the Institute for Adaptive and Neural Computation and appears in June 2005.
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2009
Variational sparse Gaussian processes
In 2009, they publish Variational Learning of Inducing Variables in Sparse Gaussian Processes at the Twelfth International Conference on Artificial Intelligence and Statistics. The method treats the inducing inputs as variational parameters and selects them, together with the kernel hyperparameters, by maximizing a lower bound of the log marginal likelihood.
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2014
Doubly stochastic variational Bayes
In 2014, the Proceedings of the 31st International Conference on Machine Learning carry Doubly Stochastic Variational Bayes for non-Conjugate Inference, which they write with Miguel Lázaro-Gredilla. The paper proposes a variational inference algorithm based on stochastic optimisation for Bayesian non-conjugate inference in continuous parameter spaces.
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By 2019
From AUEB to DeepMind
They work as a postdoctoral researcher at the University of Oxford and the University of Manchester and as an assistant professor in the Department of Informatics at the Athens University of Economics and Business. By 2019, they are a full-time research scientist at DeepMind in London, and in December 2019 they speak on Gradient-based Adaptive Markov Chain Monte Carlo at the Department of Engineering in Cambridge.
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2022
A NeurIPS Outstanding Paper
In 2022, they coauthor Gradient Estimation with Discrete Stein Operators with Jiaxin Shi, Yuhao Zhou, Jessica Hwang and Lester Mackey, which receives a NeurIPS 2022 Outstanding Paper Award. The paper introduces a variance reduction technique based on Stein operators for discrete distributions and uses it to build control variates for the REINFORCE leave-one-out estimator.
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2024
Masked diffusion for discrete data
In 2024, they coauthor Simplified and Generalized Masked Diffusion for Discrete Data at NeurIPS with Jiaxin Shi, Kehang Han, Zhe Wang and Arnaud Doucet. The paper shows that the continuous-time variational objective of masked diffusion models is a weighted integral of cross-entropy losses, and the official JAX implementation, MD4, is published in the google-deepmind GitHub organization.
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2025
Tighter sparse Gaussian process bounds
In 2025, they publish New Bounds for Sparse Variational Gaussian Processes in the Proceedings of the 42nd International Conference on Machine Learning. In Gaussian process regression, the paper derives a tractable collapsed bound that is tighter than the previous bound.
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As of October 2026
Research scientist at DeepMind
They are a full-time research scientist at Google DeepMind in London, with research interests in machine learning and statistical methodology. Their recent work includes Learning-Order Autoregressive Models with Application to Molecular Graph Generation, an ICML 2025 paper.
Career
- NowGoogle DeepMindResearch Scientist
- University of OxfordPostdoctoral Researcher
- University of ManchesterPostdoctoral Researcher
- Athens University of Economics and BusinessAssistant Professor
Education
- 2005University of EdinburghPhD
- University of Ioannina
Sources and credits
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- Michalis Titsias
- Unsupervised Learning of Multiple Objects in Images
- Variational Learning of Inducing Variables in Sparse Gaussian Processes
- Doubly Stochastic Variational Bayes for non-Conjugate Inference
- [AI@AUEB/ML Group Meeting - Seminar Series] Invited talk: Simplified and Generalized Masked Diffusion for Discrete Data
- Michalis K. Titsias, Athens University of Economics and Business
- talks.cam : LR11, Department of Engineering
- Recent publications · Michalis Titsias
- Research Focus: Week of December 5, 2022 - Microsoft Research
- Simplified and Generalized Masked Diffusion for Discrete Data
- GitHub - google-deepmind/md4: Official Jax Implementation of MD4 Masked Diffusion Models
- New Bounds for Sparse Variational Gaussian Processes
