Yara Okonkwo, PhD candidate
PhD candidate in Machine Learning
Department of Computer Science, Harwell Institute of Technology · Bristol, United Kingdom
Education
- PhD in Computer Science (Machine Learning), Harwell Institute of Technology, Bristol, UK — expected 2026. Thesis: 'Efficient Uncertainty Quantification in Large-Scale Graph Neural Networks'. Supervisor: Prof. R. Castellano.
- MSc in Artificial Intelligence (Distinction), Harwell Institute of Technology, Bristol, UK — 2021.
- BSc in Mathematics and Computer Science (First Class Honours), University of Midvale, Birmingham, UK — 2020.
Research experience
- Graduate Research Assistant, Adaptive Learning Systems Lab, Harwell Institute of Technology, 2021–present. Developing scalable Bayesian inference methods for graph-structured data; maintaining the lab's open-source benchmarking toolkit.
- Research Intern, DeepSense AI (industry), London, UK, Summer 2023. Investigated test-time adaptation strategies for distribution-shifted medical imaging; work incorporated into internal product pipeline.
- Undergraduate Research Assistant, Optimisation and Learning Group, University of Midvale, 2019–2020. Implemented gradient-free optimisation baselines for hyperparameter search; contributed to codebase used in two subsequent lab publications.
Publications
- [1] Y. Okonkwo, R. Castellano, and P. Ferreira, 'Calibrated Posterior Estimates for Node Classification via Stochastic Depth Sampling,' in Proc. Int. Conf. Neural Information Processing Systems (NIPS-X), Montreal, Canada, Dec. 2023, pp. 4812–4825.
- [2] Y. Okonkwo and R. Castellano, 'Laplacian Dropout Regularisation for Graph Convolutional Networks,' in Proc. Int. Conf. Learning Representations (ICLR-W), Workshop on Geometrical and Topological Representation Learning, Vienna, Austria, May 2023.
- [3] Y. Okonkwo, S. Ndiaye, and L. Hartman, 'BenchGNN: A Reproducible Evaluation Suite for Uncertainty in Graph Neural Networks,' arXiv preprint arXiv:2311.09182, 2023. [Preprint]
- [4] S. Ndiaye, Y. Okonkwo, and R. Castellano, 'Scalable Variational Inference for Deep Graph Models,' IEEE Trans. Neural Netw. Learn. Syst., vol. 35, no. 4, pp. 1923–1936, Apr. 2024. doi:10.0000/tnnls.2024.00412
- [5] Y. Okonkwo, T. Bergstrom, and R. Castellano, 'Test-Time Uncertainty Adaptation under Covariate Shift for Medical Image Segmentation,' in Proc. IEEE/CVF Conf. Computer Vision and Pattern Recognition Workshops (CVPRW), Seattle, USA, Jun. 2024, pp. 301–308.
Teaching
- Teaching Assistant, CS3420 — Deep Learning (undergraduate), Harwell Institute of Technology, Spring 2024. Delivered weekly lab sessions (60 students); designed three assessed practicals in PyTorch.
- Teaching Assistant, CS2210 — Algorithms and Data Structures (undergraduate), Harwell Institute of Technology, Autumn 2022 and Autumn 2023. Led problem-solving tutorials; held weekly office hours.
- Guest Lecturer, MSc AI Research Methods module, Harwell Institute of Technology, Feb. 2024. One-hour lecture on 'Reproducibility and Open Science in Machine Learning'.
Conference presentations
- Oral presentation: 'Calibrated Posterior Estimates for Node Classification via Stochastic Depth Sampling,' NIPS-X, Montreal, Canada, Dec. 2023.
- Poster: 'Laplacian Dropout Regularisation for Graph Convolutional Networks,' ICLR-W Workshop on Geometrical and Topological Representation Learning, Vienna, Austria, May 2023.
- Poster: 'Test-Time Uncertainty Adaptation under Covariate Shift,' CVPRW, Seattle, USA, Jun. 2024.
- Talk: 'Open Benchmarking Practices for Graph Neural Networks,' UK Machine Learning PhD Symposium, Edinburgh, UK, Sep. 2023.
Awards & honours
- EPSRC Doctoral Training Partnership Studentship (full fees + stipend), 2021–2025.
- Best Student Paper Runner-Up, UK Machine Learning PhD Symposium, 2023.
- Faculty Prize for Outstanding MSc Dissertation, Harwell Institute of Technology, 2021.
- Dean's List, University of Midvale, 2018–2020.
Skills
- Programming languages: Python (expert), C++ (proficient), Julia (familiar), Bash.
- ML frameworks: PyTorch, PyTorch Geometric, JAX, scikit-learn, Hugging Face Transformers.
- Tools & infrastructure: Git, Docker, Weights & Biases, SLURM (HPC), LaTeX.
- Research methods: Bayesian deep learning, graph neural networks, uncertainty quantification, distribution shift, reproducibility.
- Languages: English (native), French (intermediate).