Alexander Erreygers

I am a postdoctoral researcher at Ghent University, more precisely at the Foundations Lab for imprecise probabilities (FLip) of the Department of Electronics and Information Systems, part of the Faculty of Engineering and Architecture.

Alexander Erreygers My research is focussed around the theory and applications of imprecise probabilities. On the theoretical side, I am currently working on stochastic processes, mainly on (an imprecise extension of) the Poisson process and on Markovian imprecise jump processes – also known as imprecise continuous-time Markov chains.

If interested, you can scroll down to take a look at my scientific output, brief academic CV or contact details.


Scientific output

Journal articles

  1. Alexander Erreygers & Jasper De Bock. Markovian imprecise jump processes: Extension to measurable variables, convergence theorems and algorithms. In International Journal of Approximate Reasoning, 147:78–124, Aug. 2022.
  2. Alexander Erreygers & Enrique Miranda. A graphical study of comparative probabilities. In Journal of Mathematical Psychology, 104:102582, Sep. 2021.
  3. Alexander Erreygers & Jasper De Bock. Bounding inferences for large-scale continuous-time Markov chains: A new approach based on lumping and imprecise Markov chains. In International Journal of Approximate Reasoning, 115:96–133, Dec. 2019.
  4. Alexander Erreygers, Jasper De Bock, Gert de Cooman & Arthur Van Camp. Optimal control of a linear system subject to partially specified input noise. In International Journal of Robust and Nonlinear Control, 29(12):3892–3914, Aug. 2019.
  5. Alexander Erreygers, Cristina Rottondi, Giacomo Verticale & Jasper De Bock. Imprecise Markov Models for Scalable and Robust Performance Evaluation of Flexi-Grid Spectrum Allocation Policies. In IEEE Transactions on Communications, 66(11):5401–5414, Nov. 2018.

Articles in conference proceedings

  1. Yema Paul, Alexander Erreygers & Jasper De Bock. Expected time averages in Markovian imprecise jump processes: A graph-theoretic characterisation of weak ergodicity. In the proceedings of the 13th International Symposium on Imprecise Probability: Theories and Applications (ISIPTA 2023), Jul. 2023.
  2. Alexander Erreygers. Sublinear expectations for countable-state uncertain processes. In the proceedings of the 13th International Symposium on Imprecise Probability: Theories and Applications (ISIPTA 2023), Jul. 2023.
  3. Arne Decadt, Alexander Erreygers, Jasper De Bock & Gert de Cooman. Decision-making with E-admissibility given a finite assessment of choices. In the proceedings of the 10th International Conference on Soft Methods in Probability and Statistics (SMPS 2022), Aug. 2022.

    Winner of a Gold International Journal of Approximate Reasoning Best Paper Award.

  4. Alexander Erreygers & Jasper De Bock. Extending the domain of imprecise jump processes from simple variables to measurable ones. In the proceedings of the 12th International Symposium on Imprecise Probability: Theories and Applications (ISIPTA 2021), Jul. 2021.
  5. Jasper De Bock, Alexander Erreygers & Thomas Krak. Sum-product laws and efficient algorithms for imprecise Markov chains. In the proceedings of the 37th Conference on Uncertainty in Artificial Intelligence (UAI 2021), Jun. 2021.
  6. Alexander Erreygers & Enrique Miranda. A study of the set of probability measures compatible with comparative judgements. In the proceedings of the 18th International Conference on Information Processing and Management of Uncertainty in Knowledge-Based Systems (IPMU 2020), Jun. 2020.
  7. Alexander Erreygers & Jasper De Bock. First steps towards an imprecise Poisson process. In the proceedings of the 11th International Symposium on Imprecise Probability: Theories and Applications (ISIPTA 2019), Jun. 2019.
  8. Thomas Krak, Alexander Erreygers & Jasper De Bock. An Imprecise Probabilistic Estimator for the Transition Rate Matrix of a Continuous-Time Markov Chain. In the proceedings of the 9th International Conference on Soft Methods in Probability and Statistics (SMPS 2018), Sep. 2018.
  9. Alexander Erreygers & Jasper De Bock. Computing Inferences for Large-Scale Continuous-Time Markov Chains by Combining Lumping with Imprecision. In the proceedings of the 9th International Conference on Soft Methods in Probability and Statistics (SMPS 2018), Sep. 2018.

    Winner of the International Journal of Approximate Reasoning Best Paper Award.

  10. Alexander Erreygers & Jasper De Bock. Imprecise continuous-time Markov chains: Efficient Computational methods with guaranteed error bounds. In the proceedings of the 10th International Symposium on Imprecise Probability: Theories and Applications (ISIPTA'17), Jul. 2017.
  11. Cristina Rottondi, Alexander Erreygers, Giacomo Verticale & Jasper De Bock. Modelling spectrum assignment in a two-service flexi-grid optical link with imprecise continuous-time Markov chains. In the proceedings of the 13th International Conference on the Design of Reliable Communication Networks (DRCN 2017), Mar. 2017.

    Winner of the best paper award.

Posters and presentations

  1. Alexander Erreygers. One way to define an imprecise-probabilistic version of the Poisson process. Invited talk for the SIPTA Seminar series, 16 Jun. 2023.
  2. Alexander Erreygers. Imprecise (Markovian) processes: Beyond finitary variables. Presented at the Workshop on Imprecise Probability and Robust Finance (ImPRooF), 20 Sep. 2022.
  3. Alexander Erreygers. Markoviaanse imprecieze sprongprocessen: grondslagen, algoritmen en toepassingen. Presenstation (in Dutch) for the final round of the `AIG-prijs`, 2 Jun. 2022.
  4. Alexander Erreygers. Extending the domain of Markovian imprecise jump processes. Presented at the International Conference on Uncertainty Quantification & Optimisation (UQOP 2020), 17 Nov. 2020.
  5. Alexander Erreygers. Imprecise stochastic processes. Invited talk at the University of Oviedo, 11 Nov. 2019.
  6. Alexander Erreygers & Jasper De Bock. Computing limit expectations of imprecise continuous-time Markov chains. Presented at the 11th Workshop on Principles and Methods of Statistical Inference with Interval Probability (WPMSIIP 2018), 1 Aug. 2018.
  7. Alexander Erreygers & Jasper De Bock. Lumping continuous-time Markov chains. Presented at the 10th Workshop on Principles and Methods of Statistical Inference with Interval Probability (WUML/WPMSIIP 2017), 12 Sep. 2017.
  8. Alexander Erreygers & Jasper De Bock. Towards an imprecise Poisson process. Presented at the 10th Workshop on Principles and Methods of Statistical Inference with Interval Probability (WUML/WPMSIIP 2017), 12 Sep. 2017.
  9. Alexander Erreygers & Jasper De Bock. Handling the state space explosion of Markov chains: How lumping introduces imprecision (almost) inevitably. Presented at the 10th International Symposium on Imprecise Probability: Theories and Applications (ISIPTA'17), 14 Jul. 2017.
  10. Cristina Rottondi, Alexander Erreygers, Giacomo Verticale & Jasper De Bock. Modelling spectrum assignment in a two-service flexi-grid optical link with imprecise continuous-time Markov chains. Presented at the 10th International Symposium on Imprecise Probability: Theories and Applications (ISIPTA'17), 10 Jul. 2017.
  11. Alexander Erreygers, Jasper De Bock, Gert de Cooman & Arthur Van Camp. LQ optimal control for partially specified input noise. Presented at the 28th European Conference on Operational Research (EURO2016), 6 Jul. 2016.
  12. Alexander Erreygers, Jasper De Bock, Gert de Cooman & Arthur Van Camp. Optimal control of linear systems with quadratic cost and imprecise forward irrelevant input noise. Presented at the 9th International Symposium on Imprecise Probability: Theories and Applications (ISIPTA'15), 22 Jul. 2015.

Dissertation

  1. Alexander Erreygers. Markovian Imprecise Jump Processes: Foundations, Algorithms and Applications. Doctoral dissertation, Ghent University, 16 Sep. 2021.

Preprints

  1. Alexander Erreygers & Jasper De Bock. Countable-state stochastic processes with càdlàg sample paths.

Academic CV

Working experience

Postdoctoral researcher at Ghent University. Oct. 2021 – present

PhD Student at Ghent University. Oct. 2015 – Sep. 2021

I pursued my PhD under the supervision of Jasper De Bock, Gert de Cooman and Herwig Bruneel.

Engineering intern at BASF Antwerp. Aug. 2014 – Sep. 2014

During a 4 week internship I built a model of the KPI of a chemical plant using data mining techniques available in the JMP software package.

Awards

Gold IJAR Best Paper Award at SMPS 2022
Shortlisted for the AIG-prijs of 2022
IJAR Young Researcher Award at ISIPTA 2021
IJAR Best Paper Award at SMPS 2018
Best Paper Award at DRCN 2017

Teaching

Linear Systems 2021–2022 – present

This course involves the basic principles of the study of linear dynamical systems, the properties of such systems, and the most important design techniques for controlling them. Lecturer: Gert de Cooman

Probability and Statistics 2017–2018 – 2020–2021

The aim of this course is to teach the student the basic principles and the reasoning methods of probability. Lecturer: Gert de Cooman

Nonlinear Systems 2017–2018 – 2018–2019

This course discusses the notion of nonlinearity in a dynamical context in a systematic way. In the exercise sessions I supervised, the objective is to get familiar with the tools and techniques useful in the qualitative and quantitative study of the dynamics of nonlinear systems. Lecturer: Jasper De Bock

Queueing Analysis and Simulation 2015–2016 – 2016–2017

This course introduces basic concepts of queueing analysis and simulation for assessing the performance of computer and communication systems. I supervised the exercise sessions on probability theory (and Markov chains in particular), birth-death queues and queueing networks. Lecturers: Joris Walraevens and Dieter Fiems

Academic services

SIPTA School 2024

Together with Floris Persiau, I am organising the 11th SIPTA School, scheduled to take place from 12 to 16 August 2024 in Ghent, Belgium. More information is available on the school’s website.

Reviewing

I have reviewed for ISIPTA 2019, ISIPTA 2021, ISIPTA 2023, IPMU 2022, Information Fusion, the International Journal of Approximate Reasoning and Performance Evaluation.

SIPTA: Executive Editor

In February 2022, I replaced Cassio P. de Campos as Executive Editor in the Executive Committee of the Society for Imprecise Probabilities: Theories and Applications (SIPTA). In this capacity, I update and maintain the website and SIPTA blog, as well as the SIPTA mailinglists.

ISIPTA 2019

I was a member of the local organising committee of ISIPTA 2019, the 20-year anniversary edition of the International Symposium on Imprecise Probabilities: Theories and Applications. My duties included designing and managing the conference website.

Education

Doctor of Mathematical Engineering at Ghent University. Oct. 2015 – Sep. 2021

Supervisors: Jasper De Bock, Gert de Cooman & Herwig Bruneel.

MSc in Electromechanical Engineering at Ghent University. Sep. 2013 – July 2015

Option Control Engineering & Automation, graduated with greatest distinction.

BSc in Electromechanical Engineering at Ghent University. Sep. 2010 – July 2013

Graduated with great distinction.


Contact

Alexander Erreygers
Technologiepark - Zwijnaarde 125
B9052 Zwijnaarde
Belgium
alexander.erreygers@ugent.be