Artificial Intelligence
Data Science
Algorithms
archimedes-Artificial Intelligence, Data Science, Algorithms-greece
greece
Algorithms
Data Science
Artificial Intelligence
[Archimedes Talks] Sampling from high-dimensional constrained distributions
Dates
2025-03-31 12:00 - 14:00
Venue
Artemidos 1 - Amphitheater
Title: Sampling from high-dimensional constrained distributions
Speaker: Dr. Vissarion Fisikopoulos (Senior software engineer at Oracle and Coordinator of the GeomScale project)
Abstract: Sampling from a given probability distribution constrained by a convex
space is a fundamental problem that arises across various fields, from
optimization to quantitative finance and systems biology. These problems
are critical for modeling uncertainty, making decisions under
constraints, and understanding complex systems. However, designing
efficient sampling algorithms in high-dimensional spaces remains a
significant challenge.
In this talk, we will introduce the relevant theoretical background,
define the main problems, and delve into the core challenges associated
with sampling in constrained spaces. We will explore how these
challenges manifest in practical applications, briefly touching on real
world examples from biology and finance. Furthermore, we will outline
the current state-of-the-art methods available for some important
constraint models, focusing on their computational efficiency,
scalability, and accuracy.
space is a fundamental problem that arises across various fields, from
optimization to quantitative finance and systems biology. These problems
are critical for modeling uncertainty, making decisions under
constraints, and understanding complex systems. However, designing
efficient sampling algorithms in high-dimensional spaces remains a
significant challenge.
In this talk, we will introduce the relevant theoretical background,
define the main problems, and delve into the core challenges associated
with sampling in constrained spaces. We will explore how these
challenges manifest in practical applications, briefly touching on real
world examples from biology and finance. Furthermore, we will outline
the current state-of-the-art methods available for some important
constraint models, focusing on their computational efficiency,
scalability, and accuracy.
From a practical viewpoint, we will demonstrate the implementation of
these methods in open-source software, providing hands-on insights into
their implementation and applicability. The discussed software is
publicly available at \url{https://github.com/GeomScale}, enabling
researchers and practitioners to integrate these advanced sampling
techniques into their workflows.
these methods in open-source software, providing hands-on insights into
their implementation and applicability. The discussed software is
publicly available at \url{https://github.com/GeomScale}, enabling
researchers and practitioners to integrate these advanced sampling
techniques into their workflows.
Short Bio: Previously, he was a postdoc researcher at Algorithms Research Group in Université libre de Bruxelles (ULB) working with Prof. Samuel Fiorini. Before that he was a visiting researcher at National Institute for Mathematical Sciences in South
Korea and researcher at the University of Athens.
He holds a Phd in Computer Science, from University of Athens supervised by Prof. Ioannis Emiris. Also, a M.Sc. in Logic, Algorithms and Computation, from University of Athens. His diploma (5-year degree) is in Computer Engineering & Computer Science from CEID,
University of Patras.
You can attend online via MS-Teams by clicking the following link
Vision
To position Greece as a leading player in AI and Data Science
Mission
To build an AI Excellence Hub in Greece where the international research community can connect, groundbreaking ideas can thrive, and the next generation of scientists emerges, shaping a brighter future for Greece and the world
Welcome to ARCHIMEDES, a vibrant research hub connecting the global AI and Data Science research community fostering groundbreaking research in Greece and beyond. Its dedicated core team, comprising lead researchers, affiliated researchers, Post-Docs, PhDs and interns, is committed to advancing basic and applied research in Artificial Intelligence and its supporting disciplines, including Algorithms, Statistics, Learning Theory, and Game Theory organized around 8 core research areas. By collaborating with Greek and Foreign Universities and Research Institutes, ARCHIMEDES disseminates its research findings fostering knowledge exchange and providing enriching opportunities for students. Leveraging AI to address real-world challenges, ARCHIMEDES promotes innovation within the Greek ecosystem and extends its societal impact. Established in January 2022, as a research unit of the Athena Research Center with support from the Committee Greece 2021, ARCHIMEDES is funded for its first four years by the EU Recovery and Resilience Facility (RRF).
Christos Papadimitriou Speaks on “Artificial Intelligence: its History, its Present, and its Uncertain Future”
24 March 2026
Christos Papadimitriou, Donovan Family Professor of Computer Science at Columbia Engineering at Columbia University, USA, and Principal Scientist at the Archimedes Research Unit of the Athena Research Center, Greece, spoke about “Artificial Intelligence: its History, its Present, and its Uncertain Future” during the ten-year anniversary event of diaNEOsis think tank, which took place on March 11, 2026, at the Stavros Niarchos Foundation Cultural Center (SNFCC).
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24 March 2026
Vasia Papanikou, a PhD student at the University of Ioannina and an Academic fellow at Archimedes, Athena Research Center, Greece, will be demonstrating "MIMOSA: A Tool for Fairness Exploration Through Explanations" at the 29th International Conference on Extending Database Technology (EDBT/ICDT 2026), taking place from March 24–27, 2026, at Tampere, Finland.
Archimedes Academic Fellow Andreas Lolos Presents Research at WACV 2026
16 March 2026
Archimedes Academic Fellow and a third-year PhD student at the National and Kapodistrian University of Athens in Greece, Andreas Lolos recently travelled to Tucson in Arizona, USA, and presented the paper "SGPMIL: Sparse Gaussian Process Multiple Instance Learning" at the IEEE/CVF Winter Conference on Applications of Computer Vision (WACV 2026).
6 Accepted Papers at ICLR 2026
11 March 2026
The Archimedes research unit of the Athena Research Center in Greece has six papers accepted at this year's International Conference on Learning Representations (ICLR) gathering, including one oral presentation. The acceptance rate for posters was about 25,8% and about 1,1% for oral presentations. Please bear in mind that ICLR, along with NeurIPS and ICML, is considered one of the three top-tier artificial intelligence and machine learning conferences in the world.
The project “ARCHIMEDES Unit: Research in Artificial Intelligence, Data Science and Algorithms” with code OPS 5154714 is implemented by the National Recovery and Resilience Plan “Greece 2.0” and is funded by the European Union – NextGenerationEU.
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