Phuong Thuy Vo: mathematical modelling applied to biology and ecology

Phuong Thuy Vo is a member of the Evry Mathematics and Modelling Laboratory (LaMME - Univ. Paris-Saclay, National Centre for Scientific Research CNRS, Univ. d’Évry, National School of Computer Science for Industry and Business ENSIIE, French National Research Institute for Agriculture, Food and Environment INRAE). She specialises in the field of graphs and random networks, applied in particular to statistical studies in medical biology and ecology. She is also a lecturer at ENSIIE in Evry.

As a member of the Statistics & Genomics team, one of three at LAMME, Phuong Thuy Vo reflects on her young career as a mathematician and her vocation, which originated in her birthplace, Vietnam. "I've always loved mathematics," she recalls, "for the beauty of its equations and more importantly, for its relevance across so many fields of application."  After completing her scientific baccalaureate, she studied in the Department of Mathematics at the University of Hue, Vietnam, from 2010 to 2014. She was then selected for a 1st year Master’s degree at the Institute of Mathematics of the Vietnam Academy of Science and Technology. It was at this international institute, where lectures are given by professors and experts from all over the world, that the mathematician met Jean-Stéphane Dhersin, a lecturer at University Sorbonne Paris-Nord. He offered her the opportunity to obtain a scholarship to continue her studies in France.

From Vietnam to Evry

In 2016, she obtained her 2nd year Master’s degree (Applied Mathematics: Probability and Statistics) from University Sorbonne Paris-Nord. Jean-Stéphane Dhersin subsequently became her thesis director. "I specialised in random graphs applied to biology and in particular contributed to modelling the spread of epidemics." This topic proved to be premonitory as she defended her PhD thesis in the middle of the Covid-19 pandemic, in November 2020. To conclude her doctoral journey, the young mathematician taught as a temporary teaching and research assistant at Gustave Eiffel University, in Marne-la-Vallée. Following this, she embarked on a post-doctorate at the École Normale Supérieure de Lyon in the Pure and Applied Mathematics Unit (UPMA) until September 2022, when she was recruited as lecturer at LAMME.

Improving random models

Phuong Thuy Vo's research focuses primarily on the mathematical theory of random graphs. She addresses the theoretical aspects of probabilistic and statistical issues applied to different fields. "During my thesis, for instance, I developed a complex theoretical model applied to the statistics of drug-using populations. This model is based on specific random graph models, such as the Erdös-Rényi model, combined with stochastic methods." The aim is to identify the "invisible" individuals in statistics, meaning those not accounted for because they are hard to access. This operation is carried out with as few biases as possible, using a sample from this population. "We conduct the theoretical part by developing a sampling method, which we then test on this type of population."

Modelling a medical diagnosis...

"You can model all phenomena with mathematics!" exclaims Phuong Thuy Vo. She is currently involved in various research projects and is branching into new fields. "I'm now focusing on machine learning and artificial intelligence applied to biology and ecology. I am particularly interested in the numerous applications of deep learning and Big Data." She is working closely with colleagues from all disciplinary backgrounds, mainly at Université Paris-Saclay and elsewhere in France. She is continuing a collaboration that began during her post-doctorate with the École Normale Supérieure de Lyon on a project in the field of life sciences. The mathematician is also developing a chair in machine learning and statistical learning applied to the challenges of medical diagnosis, in partnership with colleagues from Toulouse and the National Institute for Research in Digital Science and Technology (INRIA) Bretagne. "I'm working on a project for the early detection of skin cancer. For me, this is simply about advancing healthcare," she enthuses. “The aim is to assist doctors by considerably reducing their workload at the start of their medical diagnosis. The machine can indeed detect cancer in record time. Our role then is to evaluate the uncertainty of the prediction in the machine learning models used."

... or a climate statistic

Phuong Thuy Vo also wants to study statistical motion learning to model climate-related issues. In fact, she explored these subjects during her thesis, through her involvement in the Mathematical Modelling and Biodiversity Chair led by Sylvie Méléard. She did the same during her postdoc, working on the "Mathematics and Biodiversity" project designed to model the evolution of phenotypic variations under environmental impacts.

Promoting ties with Vietnam

While Phuong Thuy Vo teaches third-year undergraduate and first-year master's students at ENSIIE, she admits a preference for research but finds teaching to be "an excellent way to disseminate her research by discussing it with students. Importantly, it helps to identify the most motivated among them and recruit them for internships in the laboratory." In particular, the mathematician leads the "research project" course, which introduces students to research by teaching them, for example, how to read publications related to the disciplines taught. As ENSIIE predominantly attracts male students, there are even fewer female students drawn to research in mathematics. However, Phuong Thuy Vo doesn't try to influence them, believing "the most important thing is to do what you want to do." Nonetheless, the mathematician is actively involved in developing relationships between ENSIIE and the academic world in Vietnam. "I received a very warm welcome when I arrived here and was granted a scholarship from the French Government's Mathematics Foundation, which greatly assisted me in my daily life. I would now like to recruit Vietnamese students and help them pursue their studies in France," she concludes.