Category Archives: Uncategorized

Jan Günter Wöhlke

You are all cordially invited to the AMLab seminar on Thursday 20th February at 16:00 in C3.163, where Jan Günter Wöhlke from Boschwill give a talk titled “Tackling Sparse Rewards in Reinforcement Learning”

Abstract: Sparse reward problems present a challenge for reinforcement learning (RL) agents. Previous work has shown that choosing start states according to a curriculum can significantly improve the learning performance. Many existing curriculum generation algorithms rely on two key components: Performance measure estimation and a start selection policy. In our recently accepted AAMAS paper, we therefore propose a unifying framework for performance-based start state curricula in RL, which allows analyzing and comparing the influence of the key components. Furthermore, a new start state selection policy is introduced. With extensive empirical evaluations, we demonstrate state-of-the-art performance of our novel curriculum on difficult robotic navigation tasks as well as a high-dimensional robotic manipulation task.

Herke van Hoof

You are all cordially invited to the AMLab seminar on Thursday 21st November at 14:00 in C3.163, where Herke van Hoof will give a talk titled “Gradient estimation algorithms”. There are the usual drinks and snacks!

Abstract: In many cases, we cannot calculate exact gradients. This is the case if we cannot evaluate how well the model was expected to have done for different parameter values, for example if the model generates a sequence of stochastic decisions. Thus, many gradient estimators have been developed, from classical techniques from reinforcement learning to modern techniques such as the relax estimator. In e.g. meta-learning second derivative estimators have also been proposed. In this talk, I will attempt to give an overview of the properties of these techniques.

Maurice Weiler

You are all cordially invited to the AMLab seminar on Thursday 24th October at 14:00 in D1.113, where Maurice Weiler will give a talk titled “Gauge Equivariant Convolutional Networks”. There are the usual drinks and snacks!

Abstract: The idea of equivariance to symmetry transformations provides one of the first theoretically grounded principles for neural network architecture design. Equivariant networks have shown excellent performance and data efficiency on vision and medical imaging problems that exhibit symmetries. We extend this principle beyond global symmetries to local gauge transformations, thereby enabling the development of equivariant convolutional networks on general manifolds. We show that gauge equivariant convolutional networks give a unified description of equivariant and geometric deep learning by deriving a wide range of models as special cases of our theory. To illustrate our theory on a simple example and highlight the interplay between local and global symmetries we discuss an implementation for signals defined on the icosahedron, which provides a reasonable approximation of spherical signals. We evaluate the Icosahedral CNN on omnidirectional image segmentation and climate pattern segmentation, and find that it outperforms previous methods.

Sindy Löwe

You are all cordially invited to the AMLab seminar on Thursday 14th November at 14:00 in C3.163, where Sindy Löwe will give a talk titled “Putting An End to End-to-End: Gradient-Isolated Learning of Representations”. There are the usual drinks and snacks!

Abstract: We propose a novel deep learning method for local self-supervised representation learning that does not require labels nor end-to-end backpropagation but exploits the natural order in data instead. Inspired by the observation that biological neural networks appear to learn without backpropagating a global error signal, we split a deep neural network into a stack of gradient-isolated modules. Each module is trained to maximally preserve the information of its inputs using the InfoNCE bound from Oord et al. [2018]. Despite this greedy training, we demonstrate that each module improves upon the output of its predecessor, and that the representations created by the top module yield highly competitive results on downstream classification tasks in the audio and visual domain. The proposal enables optimizing modules asynchronously, allowing large-scale distributed training of very deep neural networks on unlabelled datasets.

PhD student Noud de Kroon joined AMLab

Noud de Kroon has joined the UvA in October 2018 as a PhD student of AMLab, under the joint supervision of dr. Joris Mooij and dr. Danielle Belgrave (Microsoft Research Cambridge). Previously, he obtained a bachelor’s degree in software science at Eindhoven University of Technology and a master’s degree in computer science at the University of Oxford. His research focus is on combining causality and reinforcement learning in order to make better
decisions and improve data efficiency, with applications for example in the medical domain.

Talk by Matthias Reisser

You are all cordially invited to the AMLab seminar at Tuesday June 21 at 16:00 in C3.163, where Matthias Reisser will give a talk titled “Distributed Bayesian Deep Learning”. Afterwards there are the usual drinks and snacks!

Abstract: I would like to give you an overview on what my PhD topic going to be about, as well as present my first project along with initial results: Although deep learning becomes more and more data efficient, it is still true that with more data, more complex models with better generalization capabilities can be trained. More data and bigger models require more computation, resulting in longer training times and slow experiment cycles. One valid approach to speed up computations is by distributing them across machines. At the same time, in the truly huge data regime, as well as for privacy reasons, data may not be accessible from any machine, requiring distributed computations. In a first project, we look at variational inference and a principled approach to distributed training of one joint model. I am looking forward to your opinion and will be grateful for any feedback. Although I am a QUVA member, every UVA-employee is welcome to attend, independent on whether you have signed the QUVA NDA.

Talk by Matthijs Snel

You are all cordially invited to the AMLab seminar at Tuesday May 31 at 16:00 in C3.163, where Matthijs Snel from Optiver will give a talk titled “An introduction to market making and data science at Optiver”. Afterwards there are the usual drinks and snacks!

AbstractOptiver is an electronic market maker with significant presence on equity and derivatives exchanges around the world. Our automated trading strategies operate as semi-autonomous agents, processing information and making multiple decisions in the blink of an eye. In this talk, I will explain some basic market making concepts, supported by real-world examples of market microstructure. I will also provide an overview of what kind of data and challenges our strategies and machine learning applications deal with.