Dear researchers,
Centrum Wiskunde & Informatica (CWI) kindly invites you to the fifth
Seminar++ meeting on Machine Learning Theory, taking place on Wednesday
May 10 from 15:00 - 17:00. These Seminar++ meetings consist of a
one-hour lecture building up to an open problem, followed by an hour of
brainstorming time. The meeting is intended for interested researchers
including PhD students. These meetings are freely accessible without
registration. Cookies, coffee and tea will be provided in the half-time
break.
The meeting of 10 May will be hosted by:
Rianne de Heide <https://riannedeheide.github.io/> (Assistant Professor
at the Vrije Universiteit Amsterdam <https://vu.nl/>)
*Multiple testing with e-values: overview and open problems*
Abstract: Researchers in genomics and neuroimaging often perform
hundreds of thousands of hypothesis tests simultaneously. The scale of
these multiple hypothesis testing problems is enormous, and with extreme
dimensionality comes extreme risk for false positives. The field of
multiple testing addresses this problem in various ways. Recently, the
new theory of hypothesis testing with e-values has been brought to the
field of multiple testing. In this talk I will give an overview of the
most important frameworks in multiple testing and recent developments in
multiple testing with e-values. Finally, I will open the discussion for
open problems in this area, focusing on FDP estimation and confidence
with e-values. This will create a framework for fully interactive
multiple testing.
The event takes place in room L016 in the CWI building, Science Park
123, Amsterdam.
The Seminar++ Meetings are part of the Machine Learning Theory Semester
Programme
<https://www.cwi.nl/en/events/cwi-research-semester-programs/research-progra…>,
which runs in Spring 2023.
Best regards on behalf of CWI from the program committee,
Wouter Koolen
Dear researchers,
Centrum Wiskunde & Informatica (CWI) kindly invites you to the fourth
Seminar++ meeting on Machine Learning Theory, taking place on Wednesday
April 19 from 15:00 - 17:00. These Seminar++ meetings consist of a
one-hour lecture building up to an open problem, followed by an hour of
brainstorming time. The meeting is intended for interested researchers
including PhD students. These meetings are freely accessible without
registration. Cookies, coffee and tea will be provided in the half-time
break.
The meeting of 19 April will be hosted by:
Dirk van der Hoeven <http://dirkvanderhoeven.com/about> (Postdoc at the
University of Amsterdam <https://www.uva.nl/>)
High-Probability Risk Bounds via Sequential Predictors
*Abstract:* Online learning methods yield sequential regret bounds under
minimal assumptions and provide in-expectation results in statistical
learning. However, despite the seeming advantage of online guarantees
over their statistical counterparts, recent findings indicate that in
many important cases, regret bounds may not guarantee high probability
risk bounds. In this work we show that online to batch conversions
applied to general online learning algorithms are more powerful than
previously thought. Via a new second-order correction to the loss
function, we obtain sharp high-probability risk bounds for many
classical statistical problems, such as model selection aggregation,
linear regression, logistic regression, and—more generally—conditional
density estimation. Our analysis relies on the fact that many online
learning algorithms are improper, as they are not restricted to use
predictors from a given reference class. The improper nature enables
significant improvements in the dependencies on various problem
parameters. In the context of statistical aggregation of finite
families, we provide a simple estimator achieving the optimal rate of
aggregation in the model selection aggregation setup with general
exp-concave losses.
*First open problem:* This open problem will be the main focus of the
seminar. The result for logistic regression is nearly optimal and the
algorithm is computationally efficient in the sense that the runtime is
polynomial in the relevant problem parameters. However, it is a
polynomial with a very high degree, making the algorithm practically not
very useful for reasonable problem parameters. For in expectation
guarantees it is known how to reduce the runtime to /d^2 T/ at the cost
of a slightly worse excess risk bound, where /d/ is the dimension of the
problem and /T/ is the number of datapoints. Unfortunately it is not
immediately clear how to use the ideas from the faster algorithm to
obtain a high-probability excess risk bound with a /d^2 T/ runtime
algorithm. This open problem asks for the following: can we obtain a
reasonable excess risk bound with high-probability in /d^2 T/ runtime
for logistic regression.
*Second open problem:* Our results heavily rely on a particular
inequality for exp-concave losses. I would like to extend our ideas to a
different class of loss function, namely self-concordant loss functions.
Given previous results in statistical learning literature (see
https://arxiv.org/pdf/2105.08866.pdf), I expect this to be possible.
The event takes place in room L016 in the CWI building, Science Park
123, Amsterdam.
The Seminar++ Meetings are part of the Machine Learning Theory Semester
Programme <https://www.cwi.nl/~wmkoolen/MLT_Sem23/index.html>, which
runs in Spring 2023.
Best regards on behalf of CWI from the program committee,
Wouter Koolen
Dear colleagues,
Centrum Wiskunde & Informatica (CWI) kindly invites you to a lecture
afternoon focused on theory of machine learning, with two distinguished
speakers that will focus on philosophical and technical challenges in
learning to model and explore the unknown environment.
The program on 12 April:
14.00 Jonas Peters <http://web.math.ku.dk/~peters/> (University of
Copenhagen): /Recent Advances in Causal Inference/
15.00 Break
15.30 Tor Lattimore <https://tor-lattimore.com/> (DeepMind): /The Curse
and Blessing of Curvature for Zeroth-order Convex Optimisation/
16.30 Reception
The first talk will be delivered remotely, the second live. For further
details, please check the abstracts below and the website
<https://www.cwi.nl/en/events/cwi-research-semester-programs/mid-semester-le…>.
These research-level lectures are intended for a non-specialist
audience, and are freely accessible.
The event takes place in the Amsterdam Science Park Congress Centre.
This "Mid Semester Lecture", marks the half-way point of the Machine
Learning Theory Semester Programme
<https://www.cwi.nl/en/events/cwi-research-semester-programs/research-progra…>,
which runs in Spring 2023. Researchers in Machine Learning Theory may
also be interested in the ongoing Seminar++ meetings
<https://www.cwi.nl/en/events/cwi-research-semester-programs/seminar-part-4-…>
every other Wednesday.
Best regards on behalf of CWI from the program committee,
Wouter Koolen
Tor Lattimore
/The Curse and Blessing of Curvature for Zeroth-order Convex Optimisation/
*Abstract:* Zeroth-order convex optimisation is still quite poorly
understood. I will tell a story about how to use gradient-based methods
without access to gradients and explain how curvature of the loss
function plays the roles of both devil and angel. The main result is a
near-optimal sample-complexity analysis of a simple and computationally
efficient second-order method applied to a quadratic surrogate loss.
The talk is based on a recent paper <https://arxiv.org/abs/2302.05371>
with András György.
Jonas Peters/
Recent Advances in Causal Inference/
*Abstract:* see website
<https://www.cwi.nl/en/events/cwi-research-semester-programs/mid-semester-le…>
To Whom It May Concern:
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Dear Colleagues,
Greetings from Machines, MDPI! We are getting in touch to ask whether
you plan on submitting work in the Special Issue "Machine Learning in
Autonomous Driving", which is edited by Prof. Dr. Young-guk Ha of Konkuk
University.
SI Link: https://www.mdpi.com/journal/machines/special_issues/HN1P17643G
The aim of this Special Issue is to present recent advances and
challenges in the application of machine learning technology in
autonomous driving, including in driving data preparation, object
detection, trajectory prediction, driving situation awareness, vehicle
localization, driving action planning, and vehicle control. This would
be a good opportunity to gather researchers in developing machine
learning models and algorithms for autonomous driving to discuss and
share original research works and practical experiences.
If you have any questions, please feel free to contact me. Expect your
reply at your first convenience.
Kind regards,
Wilda Wang
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Dear researchers,
Centrum Wiskunde & Informatica (CWI) kindly invites you to the third
Seminar++ meeting on Machine Learning Theory, taking place on Wednesday
April 5 from 15:00 - 17:00. These Seminar++ meetings consist of a
one-hour lecture building up to an open problem, followed by an hour of
brainstorming time. The meeting is intended for interested researchers
including PhD students. These meetings are freely accessible without
registration. Cookies, coffee and tea will be provided in the half-time
break.
The meeting of 5 April will be hosted by:
Patrick Forré <http://amlab.science.uva.nl/people/PatrickForre/>
(Assistant professor at the University of Amsterdam <https://www.uva.nl/>)
A convenient foundation of probability theory for probabilistic
programming, graphical models, causality and statistics
*Abstract:* Random functions and functions whose outputs are random
functions arise in many areas of statistics, probability theory and
computer science, like probabilistic graphical models, causality, the
area of conditional independence, probabilistic programming, etc.
Despite their frequent appearances the usual measure-theoretic
foundations of probability theory are not capable of properly describing
such random functions. To avoid typical work-arounds, which often come
with inconvenient restrictions, in this talk, we describe how one can
instead fix the foundations of probability theory by introducing
‘quasi-measurable spaces’, which then replace the role of measurable
spaces. We then demonstrate how the mentioned problems are solved in
this framework and further other convenient properties. Furthermore, we
show how one can rigorously express probabilistic graphical models and
typical causal assumptions using quasi-measurable spaces.
The event takes place in room L016 in the CWI building, Science Park
123, Amsterdam.
The Seminar++ Meetings are part of the Machine Learning Theory Semester
Programme <https://www.cwi.nl/~wmkoolen/MLT_Sem23/index.html>, which
runs in Spring 2023.
Best regards on behalf of CWI from the program committee,
Wouter Koolen
The AI Department of the Donders Centre for Cognition (DCC), embedded in the Donders Institute for Brain, Cognition and Behaviour, and the School of Artificial Intelligence at Radboud University Nijmegen are looking for a researcher in reinforcement learning with an emphasis on safety and robustness, an interest in natural computing as well as in applications in neurotechnology and other domains such as robotics, healthcare and/or sustainability. You will be expected to perform top-quality research in (deep) reinforcement learning, actively contribute to the DBI2 consortium, interact and collaborate with other researchers and specialists in academia and/or industry, and be an inspiring member of our staff with excellent communication skills. You are also expected to engage with students through teaching and master projects not exceeding 20% of your time.
Profile:
* You have a PhD degree in Artificial Intelligence, Computer Science or a related discipline;
* You have experience in a number of the following topics: (deep, Bayesian, safe) RL, control theory and model predictive control, applications of RL in e.g. healthcare, robotics, neurotechnology, sustainability and/or edge solutions for control of complex systems.
* You have an excellent track record in scientific research, as evidenced by publications in top-tier conferences and journals.
* You have a proven ability to provide inspiring teaching in English.
* You are enthusiastic and you are able to work together in a team as part of the DBI2 consortium.
Application deadline: April 7th
To apply, please follow this link: https://www.ru.nl/en/working-at/job-opportunities/researcher-in-reinforceme…
Dear researchers,
Centrum Wiskunde & Informatica (CWI) kindly invites you to the second
Seminar++ meeting on Machine Learning Theory, taking place on Wednesday
March 22 from 15:00 - 17:00. These Seminar++ meetings consist of a
one-hour lecture building up to an open problem, followed by an hour of
brainstorming time. The meeting is intended for interested researchers
including PhD students. These meetings are freely accessible without
registration. Cookies, coffee and tea will be provided in the half-time
break.
The meeting of 22 March will be hosted by:
Hanyuang Hang <https://people.utwente.nl/h.hang> (Assistant professor at
the University of Twente <https://www.utwente.nl/en/>)
Bagged k-Distance for Mode-Based Clustering Using the Probability
of Localized Level Sets
*Abstract:* We propose an ensemble learning algorithm named bagged
/k/-distance for mode-based clustering (BDMBC) by putting forward a new
measurement called the probability of localized level sets (PLLS), which
enables us to find all clusters for varying densities with a global
threshold. On the theoretical side, we show that with a properly chosen
number of nearest neighbors /k_D / in the bagged /k/-distance, the
sub-sample size /s/, the bagging rounds /B/, and the number of nearest
neighbors /k_L / for the localized level sets, BDMBC can achieve optimal
convergence rates for mode estimation. It turns out that with a
relatively small /B/, the sub-sample size /s/ can be much smaller than
the number of training data /n/ at each bagging round, and the number of
nearest neighbors /k_D / can be reduced simultaneously. Moreover, we
establish optimal convergence results for the level set estimation of
the PLLS in terms of Hausdorff distance, which reveals that BDMBC can
find localized level sets for varying densities and thus enjoys local
adaptivity. On the practical side, we conduct numerical experiments to
empirically verify the effectiveness of BDMBC for mode estimation and
level set estimation, which demonstrates the promising accuracy and
efficiency of our proposed algorithm.
The event takes place in room L016 in the CWI building, Science Park
123, Amsterdam.
The Seminar++ Meetings are part of the Machine Learning Theory Semester
Programme <https://www.cwi.nl/~wmkoolen/MLT_Sem23/index.html>, which
runs in Spring 2023.
Best regards on behalf of CWI from the program committee,
Wouter Koolen
Dear all,
At the end of this month there will be an interesting *workshop on
**Game theory for AI *organized by the Maastricht Centre Mathematics
(MCM) together with the *AI and Mathematics (AIM)***initiative. See
below for details.
Best regards,
Tim
-------- Forwarded Message --------
Subject: AIM news - Game AI workshop & NMC
Date: Mon, 27 Feb 2023 15:38:23 +0000
From: AI and Mathematics <aim(a)NWO.NL>
To: AI and Mathematics <aim(a)NWO.NL>
*News*
·*Workshop “Game theory for AI - Mathematical foundations, Algorithms
and Future Challenge” @ Maastricht***
The Maastricht Centre Mathematics MCM & *AIM* are organizing a workshop
on "Game theory for AI - Mathematical foundations, Algorithms and Future
Challenge. The aim of this workshop is to create a new research agenda
involving the Dutch AI community along a selected list of important
topics. The research discussions will be guided and supported by the
input of leading experts in the field. Beside networking opportunities,
we aim for developing new research collaborations, connecting
researchers with different expertises. Scientists at all levels of their
career are invited to participate, but registrations will only be
accepted on a first-come-first-serve basis. The four work packages are
described below, as well as further information about location,
registration and accommodation. We are looking forward to welcome you
all in Maastricht!
/Work//Package Leader/
Online learning in complex environments Tim
van Erven (UvA)
Game AI & Search Wouter Koolen (CWI)
Robust AI via optimal transport & mean field games Christoph
Brune (U Twente)
Fast methods for large-scale bi-level programming Tristan van Leeuwen (CWI)
/Venue and Dates:/
* /_Date_/: March 30 and 31, 2023. Lunches and coffee breaks will be
provided.
* /_Location_/: Department of Advanced Computing Sciences (DACS),
Faculty of Sciences and Engineering, Maastricht University,
Paul-Henri Spaaklaan 1, 6229 EN, Maastricht.
* /_Registration_/: Registration via the AIM website.
<https://eur05.safelinks.protection.outlook.com/?url=https%3A%2F%2Faimath.nl…>__We
might be able to reimburse a limited number of participants for
their accommodation. If support is needed, please mention this in
the open text box in the registration
* /_Contact:_/Mathias Staudigl (UM), Barbara Franci (UM)
·*Dutch Mathematics Congres (NMC) on 11 & 12 April @Utrecht***
The Dutch Mathematics Congres (NMC) brings together mathematicians from
all disciplines to exchange ideas, learn from each other & network. The
NMC has 4 inspiring keynote speakers, parallel sessions, award
ceremonies, speed dates and workshops. In a plenary session organized by
*AIM, *Johannes Schmidt-Hieber will give a presentation about
statistical learning in biological neural networks. NMC takes place on
11 & 12 April 2023 at Van der Valk Hotel Utrecht. Check out the website
and the flyer attached and register for NMC!
<https://mathematischcongres.nl/>
Dear researchers,
Centrum Wiskunde & Informatica (CWI) kindly invites you to the first
Seminar++ meeting on Machine Learning Theory, taking place on Wednesday
March 8 from 15:00 - 17:00. These Seminar++ meetings consist of a
one-hour lecture building up to an open problem, followed by an hour of
brainstorming time. The meeting is intended for interested researchers
including PhD students. These meetings are freely accessible without
registration. Cookies and tea will be provided in the half-time break.
The meeting of 8 March will be:
Julia Olkhovskaya (Department of Mathematics of the Vrije Universiteit
Amsterdam)
Online reinforcement learning with linear function approximation:
role of the choice of policy optimization algorithm and learner’s
feedback
*Abstract:* We consider learning in an adversarial MDP, where the loss
function can change arbitrarily between episodes, and we assume that the
Q-function of any policy is linear in some known features. We discuss
two recent works, providing new insights into the solution to this
problem ([1], [2]). We will look at the combination of methods proposed
in these two papers to achieve better theoretical guarantees on the
performance of the algorithms. More precisely, we will check if taking
the best from both papers can lead to an improvement: exploration
bonuses from [1] and the choice of the regularizer from [2]. If there
will be time, we also discuss the variation of this problem when the
information available to the learner is only the cumulative loss of the
learner accumulated over the episode.
* [1] https://arxiv.org/pdf/2301.13087.pdf
* [2] https://arxiv.org/pdf/2301.12942.pdf
The event takes place in room L016 in the CWI building, Science Park
123, Amsterdam.
The Seminar++ Meetings are part of the Machine Learning Theory Semester
Programme <https://www.cwi.nl/~wmkoolen/MLT_Sem23/index.html>, which
runs in Spring 2023.
Best regards on behalf of CWI from the program committee,
Wouter Koolen
Dear all,
The Leiden Institute of Advanced Computer Science (LIACS) is looking for two PhD candidates in the field of Reinforcement Learning, with an emphasis on sustainable energy.
Should you know an interested/suitable candidate, then further information is available at:
https://www.universiteitleiden.nl/vacatures/2023/kwartaal-1/23-0952-phd-can…
Best regards,
Thomas Moerland