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Waves 2025 Conference Report: Emilio McAllister Fognini

By Claire Hudson, on 21 March 2025

  1. Introduction:

The “Conference on Mathematics of Wave Phenomena 2025” was held at Karlsruhe Institute of Technology (KIT) in Karlsruhe, Baden-W”{u}rttemberg, Germany — about an hour away from Frankfurt by train — between the 24th and 28th of February.
Karlsruhe is an old and wonderful town dating back to the early 18th century, nestled between the Black Forest and the Rhine river, and was built by the old Margrave of Baden-Durlach, Karl-Wilhelm.
In fact, the city’s layout radially extends from the Margrave’s palace with all the streets converging at the palace, and it is where Karlsruhe gets its nickname — the fan city.
KIT is the largest research centre in Germany and was founded in 1815, and has a long list of renowned researchers who have worked there including Fritz Haber and Heinrich Hertz. The conference was chaired by Roland Schnaubel — an expert in hyperbolic and parabolic PDEs and spectral theory — and focused on developments in mathematical modelling, simulation and analysis of wave-type equations and phenomena; key fields in analysis and numerical analysis.

  1. My Contribution

I was invited by an ex-UCL colleague to present my unpublished work on Integrating Traditional Numerical Analysis Solvers with Learnable Operators, in a minisymposium titled, “Intersection of Biomedical Acoustics and Machine Learning”, which was chaired by my secondary supervisor Prof. Ben Cox.
Unfortunately, I fell under the weather on the day of my Talk but I was able to present my work and it was well received by the full room I was presenting to, indicating that the focus of my work fit well within the minisymposium.
Despite being the only person at the conference researching the budding field of Neural Operators, there was a good amount of overlap of concepts and techniques with my fellow researchers in the minisymposium.
The talks by Andreas Hauptmann (Fast Fourier models in circular geometry for learned reconstructions in photoacoustic tomography) and Janek Gr”{o}hl (Tackling the photoacoustic inverse problems with semi-supervised deep learning) were of particular note as they focused on leveraging Machine Learning to accelerate or supplement traditional numerical solvers — a key area of research for me — and illuminated a new perspective on how to use ML to complement the strength of traditional techniques.

  1. Conference Highlights

Thankfully, I was only under the weather for a day and so I managed to attend and listen to many fascinating talks — even if many of them required more than the 4 years of mathematics I received during my MSci.
Some of the most Interesting talks were focused on Photoacoustic Tomography (PAT) and Reconstruction, which is an area in biomedical imaging where a pulse of light causes tissue to heat up and emit wideband Ultrasound.
PAT (and PAT reconstruction) problems are difficult to model in the forward direction (from light pulse to Ultrasound detection) and even more so in the inverse/reconstruction direction (from received Ultrasound to material properties of the tissue) due to both: the need to model the photoacoustic effect (generating sound from light in a medium), and the Ultrasound transmission and scattering problems.
This is further compounded in the inverse/reconstruction direction due to compounding error from the noisy Ultrasound transducers, causing the reconstructions to be both expensive and error artifact prone.

The notable talks on this topic at Waves 2025 were:

“Self Supervised Sparce-Data Image Reconstruction for Photoacousticsby Markus Haltmeier -This Talk focused on how to simplify PAT reconstruction by using an new sensor set up to translate a 3D problem into a 2D one, and by using ML models they developed called ‘Sparce2Inverse’ and ‘Noise2Inverse’ to either clean up the noisy data before using a classical reconstruction pipeline or to use traditional denoising techniques and then apply these models to clean up artifacts during reconstruction.

Fast Fourier models in circular geometry for learned reconstructions in photoacoustic tomography” by Andreas Hauptmann et al. — This Talk focused on the computational difficulties which data-driven end-to-end models face and discussed how they have been building more efficient forward and adjoint models with the aim of bringing the computational cost of PAT reconstruction to be small enough for common medical use.

“Tackling the photoacoustic inverse problems with semi-supervised deep learning” by Janek Gr”{o}hl et al. — This talk focused on using Generative Adversarial Networks (GANs) in order to improve the forward model for PAT problems and to aim to make the results of digital twin experiments (computer modelling of the forward PAT problem in a real world example) look more like real experimental data.

“Physics-Informed deep learning for ultrasonic imaging” by Felix Lucka — This Talk focused on concepts close to my own projects, namely incorporating traditional Algorithms formulated on wave-physics (such as delay-and-sum or f-k migration) as differentiable layers in a ML Architecture frameworks to facilitate in creatin light-weight, data-driven approaches which can be trained end-to-end for a given imaging task while only requiring a small amount of training data.

“Correlation-informed ordered dictionary learning for imaging in scattering media” by Chrysoula Tsogka et al. — This Talk also focused on using traditional numerical analysis techniques with a data-driven component, in this case this was Sparce Dictionary Learning using an encoder-decoder network, to compute super-resolution images in a scattering problem.

There were many other fascinating talks, but these were the highlights when it came to the intersection of numerical analysis and ML techniques.

  1. Final Thoughts

My time at Waves 2025 was fantastic and provided me with an excellent opportunity to interact with researchers focusing on related problems to my own and using similar ideas for architecture development, as well as a better understanding of the state of the Operator Learning and Scientific Machine Learning within specialist domains like Numerical Analysis.

My biggest take away from Waves 2025 would be that we as Machine Learning (ML) researchers should engage and interact more with domain experts to solve the complex and technical problems which traditional fields, such as modelling and biomedical imaging, face, as opposed to solving these problems on our own using increasingly larger and data-hungry models.

Or in other words, we need more Machine Learning and less Artificial Intelligence as researchers already have many existing tools which work frighteningly well, we should be focusing on improving these methods as opposed to replacing them wholesale with an end-to-end AI model — I found out that an area which many researchers were interested in was uncertainty quantification for outputs of ML and AI models.

Many of the problems which non-ML researchers and specialists are trying to solve have low amounts of training data (and in medical imaging this data is noisy as well), and thus, need solutions which are robust and can be integrated into existing frameworks without requiring an external server of GPUs to function.

Due to this, I encountered a sizable use of self-supervised or semi-supervised learning within the field in order to alleviate the lack of training data and typically a focus on either older techniques — such as dictionary learning and non-variational auto-encoders.

I think that a lot of productive and fruitful work is possible if we as ML researchers could provide domain expertise regarding techniques within ML or AI which supports the work of existing researchers and collaborate on bringing cutting edge advances in the ML and AI fields into existing fields such as numerical analysis and inverse problems.

Overall I had a great time at KIT and in Karlsruhe, it was a wonderful change of pace compared to London and a beautiful and historic city, and the conference provided me a lot of discussion time with fellow researchers and food for thought about possible research directions in the future.

WAVES 2025

Workshop Report: Mathematical Imaging and Surface Processing at the MFO: Romy Williamson

By Claire Hudson, on 26 February 2025

1 Introduction
The Mathematisches Forschungsinstitut Oberwolfach — or MFO — is a Mathematical Institute located deep in the hills of the Black Forest, far away from the distractions of civilisation. It was built by the Nazis in 1944, in a deliberately secluded location, so as to be an unlikely target for Allied bombing. This is ideal, when you want to peacefully concentrate on maths.
I attended the workshop on Mathematical Imaging and Surface Processing, from 2nd to 7th February 2025. This was organised by Mirela Ben Chen, an inspiring figure in the Geometry Processing community, along with Antonin Chambolle and Benedikt Wirth. Throughout the week, we heard a variety of talks from fields including optimal transport, inverse problems, surface representation, rendering, video generation, fluid simulation and more. We heard from researchers whose work is strongly rooted in classical theory, as well as many researchers who are either using, or investigating the properties of, machine learning techniques such as diffusion models.

Presenting Spherical Neural Surfaces.

2 Contribution
My personal contribution was to present my recently-accepted paper, Neural Geometry Processing via Spherical Neural Surfaces. This paper fitted in very well with the Surface Processing side of the workshop, and I noticed links with several of the other talks, particularly:
• Xavier Dennec (Flag Spaces and Geometric Statistics) — this had relevance to the part of my project where I find eigenfunctions of the Laplace-Beltrami operator.
• Nicholas Sharp (SpaceMesh: A Continuous Representation for Learning Manifold Surface Meshes) — Nick’s discussion of various surface representations led very nicely into my presentation of an alternative neural representation.
Please see the project webpage for more information.

Group photo, in front of Schwarzwald trees

3 Interesting People and Talks
These are the talks that stuck in my mind or inspired me the most. Listening to these talks has helped me to figure out what I like the most in terms of research topics and presentation styles, and to take cues from this to steer my own research direction and presentation style.
• Nicholas Sharp (SpaceMesh: A Continuous Representation for Learning Manifold Surface Meshes): excellent presentation style. He is also very engaging and enthusiastic in conversation. I was excited that he talked about halfedege meshes, and he mentioned properties of orbits of subalgebras of halfedge meshes, which I had figured out myself last summer, not realising it was an established thing. I am motivated and inspired to see someone that is very skilled and knowledgeable at classical geometry processing techniques, combining these thoughtfully (not blindly) with neural networks, to create algorithms that are more robust than previous neural techniques, with improved performance over classical methods.
• Albert Chern (Fluid Dynamics with Sub-Riemannian Geometry): I am amazed at his ability to produce such incredible results with such an aesthetic method (no ugly performance tricks and no magic neural net, etc). I plan to learn some Riemannian Geometry so I can understand more. I played a geometric game, trigon Blockus, with Albert Chern and others.(1)  Albert Chern also likes the Nichomachus Identity (related to the year 2025) and we have both independently tried to find a 4-dimensional
visual proof of that, so far without success.
(1) Why is it triangle, and pentagon, not trigon and pentangle?
• Florine Hartwig (Optimal Motion from Shape Change): I was really excited to see this talk, because Niloy and I had seen the original talk eighteen months ago at the Obergurgl Geometry Processing Workshop in Innsbruck, Austria. The original paper provided an elegant framework to predict the global motion of a deformable body in space, given its shape change. The follow-up paper explored how to optimally deform a shape so that its global motion matches a target motion as closely as possible.
They were able to do the optimisation quite elegantly within the framework. I enjoyed talking to Florine. We had some things in common, such as a background in pure maths, and rowing. Her work also relates to Riemannian geometry and I want to understand more.
• Robert Beinert (A Geometric Optimal Transport Framework for 3D Shape Interpolation): I liked this talk very much because I have spent some time in my research thinking about surface correspondence and shape interpolation, from the perspective of neural surfaces, but I had never considered it from an optimal transport point of view. I really liked the method and I was impressed that it worked at all, but I am not entirely convinced about its framing/applications, because it has no semantic knowledge of
the shapes so it can easily go wrong when the shapes have different-enough proportions. I spent some time talking to Robert and Simon Schwarz during the afternoon excursion, and they explained to me the meaning of Habilitation in Germany.
• Mark Gillespie (harmonic functions rendering). Quite interesting talk. It was a ‘walk on spheres’ type of thing, for rendering implicitly defined surfaces, but the assumption is that the function is harmonic, not necessarily an SDF. This fits into the category of ‘questioning a common assumption in the field’. I’m not totally sure how often this is practically useful but it’s a nice problem set up.
• Nicole Feng (heat method geodesics) This is a cool paper. It constructs geodesic distance robustly, by ‘diffusing’ oriented normals for a short time and solving a Poisson equation. I also noticed she dealt with it quite well when some audience were distracting from the talk a bit by being pedantic about what it even means to have signed distance in some odd cases. She joked about it slightly and moved on, it didn’t put her off that they didn’t like one of the examples.
• Zorah Lahner (nuclear fusion) This was a really good example of a talk that everyone found interesting and engaging even though it didn’t have any actual results. I think that is a difficult kind of talk to give and it leaves the speaker vulnerable to a lot of tricky questions. Maybe people liked it partly because the lack of answers made it a good discussion point.

4 Benefit
This workshop has provided me with great academic benefit. I have been exposed to new topics and I now have a better idea where I need to do further reading to improve my background knowledge in several areas. These areas would include Riemannian geometry, optimal transport, and diffusion. Also importantly, I have worked on soft skills such as presenting and networking.
The MFO was a very calm place to think. I enjoyed looking at the maths books in the library and playing the instruments in the music room. I need to be calm in order to think  clearly and be creative. Therefore I appreciated the effort the MFO has made to make such a conducive environment.

Standing next to the Boy Surface — which is an immersion of the Real Projective Plane into R3. The particular immersion depicted by the sculpture also minimises the Willmore functional, which measures elastic energy.

Conjoined Stellated Icosahedra.

PhD Researchers on the move: Journey to Vancouver to attend Neurips

By Claire Hudson, on 31 January 2025

Last month, CDT students travelled to Vancouver to present their work at NeurIPS, one of the largest AI conferences. The schedule was packed, with 6 conference papers and 3 workshop papers presented. The CDT is proud to sponsor and support our PhD students as they present their research at the conference, showcasing their hard work and academic excellence on an international stage!
Day 1, Tuesday: No papers were presented, but the expo, tutorials, and careers fair kept everyone occupied.

Day 2, Wednesday:

William Bankes William and his supervisor presented their work on robust data down sampling. Naive approaches to training on a subset of data can cause problems when classes in the dataset are imbalanced, with rare classes becoming even rarer. A direct result of this is the model’s ability to predict on this subset of the data decreases. To address this they proposed an algorithm called REDUCR, which downsamples data in a manner that preserves the performance of minority classes within the dataset. They show REDUCR works across a range of text and image problems achieving state of the art results. The work is available here.

Jake Cunningham also presented his work on 
Reparameterized Multi-Resolution Convolutions for Long Sequence Modelling

 

 

Day 3, Thursday
Yuchen Zhu 

Yuchen’s joint paper with Jialin Yu and Ricardo Silva from UCL Statistical Sciences, Structured Learning of CompositionalSequential Models was presented as part of the main proceedings of NeurIPS 2024. They proposed an explicit model for expressing how the effect of sequential interventions can be isolated into modules, clarifying previously unclear data conditions that allow for the identification of their combined effect at different units and time steps. The paper is here.  Additionally, together with collaborators from MPI Tuebingen, Yuchen presented a paper Unsupervised Causal Abstraction at the Causal Representation Learning workshop. Due to the lack of interpretability of current large blackbox models, they propose a methodology for causally abstracting a large model to a smaller and more interpretable model. In particular, unlike existing methods, their method does not require supervision signals from the smaller model. The paper can be found  here.

David Chanin

David presented a paper along with co-author Daniel Tan, another UCL PhD Student. They find that Contrastive Activation Addition (CAA) steering has mixed results in terms of robustness and reliability. Steering vectors tend to generalise out of distribution when they work in distribution. However, steerability is highly variable across different inputs: depending on the concept, spurious biases can substantially contribute to how effective steering is for each input, presenting a challenge for the widespread use of steering vectors. While CAA is effective on some tasks, other behaviours turn out to be unsteerable. As a result, it is difficult to ensure they will be effective on a given task of interest, limiting their reliability as a general alignment intervention. The paper is available here.

Day 4, Friday
Reuben Adams

Reuben presented his paper (co-authored with his supervisors) on extending a classic theorem in the PAC-Bayes literature to account for arbitrary outcomes, rather than simply correct or incorrect classifications. Their work provides theoretical insight into the generalisation behaviour of neural networks and the different kinds of errors they can make. Their framework can cover not just Type I and Type II errors, but any kind of error that may occur in multi class classification. You can find the paper here.

 

 

Daniel Augusto
Daniel presented a co-authored paper in collaboration with
Getúlio Vargas Foundation for the main conference track. Their work proposes a new solution to streaming variational Bayesian inference using  GFlowNets as a foundation for their methodology. This was the first work that allows high quality variational inference for discrete parameters without requiring the storage of the whole dataset. They believe this work will be useful for applications in genetics, through the inference of phylogenetic trees, for preference learning, and other big-data contexts. Their paper can be read here.

 

Day 5, Saturday 

Oscar Key Oscar, along with co-authors from Graphcore presented a poster at the workshop on Efficient Natural Language and Speech Processing. Their work considers the top-k operation, which finds the largest k items in a list, and investigates how it can be computed as quickly as possible on the parallel hardware commonly used to run AI applications. Top-k is found in many AI algorithms, so it’s useful to make it fast, e.g. a large language model might use it to select the most important parts of a long prompt. Their full paper is available here.

 

Varsha Ramineni 

Varsha presented her research at the Workshop on Algorithmic Fairness through the Lens of Metrics and Evaluation (AFME 2024). This work addresses the challenge of evaluating classifier fairness when complete datasets, including protected attributes, are inaccessible. They propose a novel approach that leverages separate overlapping datasets, such as internal datasets lacking demographic information  and external sources like census data, to construct synthetic test data with all necessary variables. Experiments demonstrate that our approach produces synthetic data with high fidelity and offers reliable fairness evaluation where real data is limited.  Varsha says that she had an incredible experience attending her first NeurIPS and presenting her work and engaging in meaningful discussions throughout the conference was a deeply rewarding experience, providing invaluable feedback and ideas as the work extends. Do reach out to her if you’d like to learn more!

 

 

 

CDT Foundational Artificial Intelligence Showcase: London. 22-24 July

By Claire Hudson, on 27 August 2024

This year, CDT students, academics and speakers along with staff and students from the prestigious Erasmus Mundus Joint Master’s Programme in AI gathered at the AI Centre for a journey into research, innovation and collaboration at the annual CDT Showcase.
The event kicked off with a session focusing on “The future of AI: Forming your own opinion on what’s coming, when it’s coming, and what we should

or shouldn’t do about it”. Here we explored AI Bias, AI and Warfare and AI Regulation – topics which sparked some lively debates and fostered a spirit of critical thinking amongst attendees.

After lunch, we heard from Dr Anthony Bourachad with his talk titled ART: AI’s final frontier” in which Dr Bourachad presented AI’s foray into the world of art and the Pandora’s box of questions this opens. His talk delved into the philosophical debates about what it means to create, the legal intricacies of ownership and moral rights, and the use of AI as a tool to analyze historical art.
This led to the next session in which we had the opportunity to view participants’ AI and Art entries during a mini museum experience. On display were over 40 entries from current CDT students and students from the Erasmus Mundus Joint Master’s Programme.  All artwork had to be original and created by the submitting artist and there were many impressive submissions, each telling a story and highlighting a wealth of creativity and innovation from the artists.
More on the winners later…..
To conclude the first day, attendees were treated to a vibrant and engaging social event at Immersive Gamebox  This immersive activity provided a welcome break from the day’s sessions and created many memorable moments whilst fostering relationships between participants. Truly a wonderful way to close the first day of the Showcase and a chance to solidify connections made during the conference sessions.
Day two started with a morning of informative presentations from CDT students in which we heard more about their research. With topics ranging from ” A Human-Centric Assessment of the Usefulness of Attribution Methods in Computer Vision” to “Latent Attention for Linear Time Transformers” to a talk on the “Theory of generative modelling – rethinking generative modelling as optimization in the space of measures”  The range of topics being presented provided a reminder about the diversity and exciting research that is being conducted from students and demonstrates why centres such as the FAI CDT are crucial to foster interdisciplinary research in this ever changing landscape.
One of the highlights of the showcase was the afternoon’s visit to the offices of Conception X.
Conception X is the UK’s leading PhD deeptech venture programme and assists PhD students to launch deeptech startups based on their research. There are two tracks available. “Project X” which is for PhD students interested in developing business skills through training designed for STEM researchers, and “Startup X” which is aimed at  PhD students ready to build startups.
During our visit, we enjoyed a welcome introduction from Dr Riam Kanso, Chief Executive Officer who spoke about how Conception X is leading the way in enabling scientists to create companies from their research. This was followed by presentations from entrepreneurs who have been successful in launching their companies with the support of Conception X and concluded with a host of questions from students all seemingly keen to find out more about the Conception X programme and how they too might launch their entrepreneurial journey.
Day three started with a visit to the Intelligent Robotics Lab at UCL East in which the group enjoyed a fast-paced morning with Professor Igor Gaponov.

 The lab is a world-leading research centre of excellence, dedicated to autonomous robotics, specializing in robots that can make decisions in the real-world and act on those. The lab covers areas from mechatronics and control to robot vision and learning, so our group were delighted to be able to hear more about the fascinating research that is emerging and would like to thank Professor Gaponov for providing such a wonderful opportunity to our group.

The final afternoon was filled with key note talks on a range of AI related topics. First up was  Avanade’s Emerging Technology R&D Engineering lead, Fergus Kidd with his talk titled ” The road to General Artificial Intelligence”. Next up was Professor Niloy Mitra and his talk on “what are Good Representations for 3D-aware Generative Models’ then we concluded with a presentation from Sophia Banno – Assistant Professor in Robotics and Artificial Intelligence at UCL and her talk looking at the future of AI and Robotics in Surgical Interventions!
All of these talks emphasized the importance of sustained innovation and collaboration in this rapidly evolving world and provided an intriguing end to the formal presentations of the CDT Showcase.

The final session was an opportunity to view and discuss a variety of posters that students had produced which represented their research. Poster sessions are always a great opportunity for researchers to share their findings in a visual format and encourage observers to delve deeper into specific areas of interest. It was inspiring to witness this session buzzing with an energy that underscores the collaborative spirit that defines the CDT showcase experience.

To close, our sponsor G-Research presented prizes for the AI and Art competition and best poster award to the following recipients
AI & ART
Judging was based on three key criteria (i) Description: convincing description that is compelling and an ability to explain the concept (ii) Novelty: originality of the idea and (iii) Aesthetics.
1st:
Romy Williamson
the convergence of perception
2nd:
Reuben Adams
Nook
3rd:
Pedro José Ferreira Moreira
UCL Summer School
4th:
Kai Biegun
In With The New
5th:
Roberta Chissich
Fores Escape
POSTER SESSION
1st:
Adrian Gheorghiu & Pedro Moreira
Joint 2nd:
Lorenz Wolf.
Mirgahney Mohamed & Jake Cunningham
4th:
Sierra Bonilla
5th:
Bernardo Perrone De Menezes Bulcao Ribeiro & Roberta Chissich

We would like to take this opportunity to thank G Research for their generous sponsorship of the AI & Art competition and Best Poster award.

Looking ahead, the connections made and ideas exchanged during these three days will continue to develop, shaping the future of AI. The Foundational Artificial Intelligence CDT Annual Conference is a platform for researchers and academics to showcase their research and innovation and this event proved to be a melting pot of ideas, insights, and networking opportunities, shaping the future landscape of AI.

We look forward to hosting the event again next year!

The FAICDT Visit UCL East!

By sharon.betts, on 27 November 2023

On Wednesday 15th November, members of all cohorts within the FAICDT visited our Robotics labs at the newly opened UCL East Campus. Prof Dimitrios Kanoulas very kindly offered up his time and expertise in showing our students around both the Marshgate and Pool Street Labs.

Our students were able to interact with the quadra-ped robots and speak with academics and other researchers about their ground breaking work in the field of AI and robotics.

The visit to UCL East’s robotics lab was impressive. We saw the Boston Dynamics robot navigate stairs and avoid obstacles, showcasing the practical applications of these technologies. The most striking moment was seeing a robot execute a backflip, which highlighted the advanced capabilities in robotics. Dimitrios Kanoulas kindly also gave us a tour around the Marshgate building! The location’s calm park setting was a nice change from the main campus environment. – Sierra Bonilla, Cohort 5

 

A great time was had by all, and we are delighted that our students have been able to connect with other researchers in the AI field here at UCL.

Understanding and Navigating the Risks of AI – By Reuben Adams

By sharon.betts, on 19 October 2023

It is undeniable at this point that AI is going to radically shape our future. After decades of effort, the field has finally developed techniques that can be used to create systems robust enough to survive the rough and tumble of the real world. As academics we are often driven by curiosity, yet rather quickly the curiosities we are studying and creating have the potential for tremendous real-world impact.

It is becoming ever more important to keep an eye on the consequences of our research, and to try to anticipate potential risks.

This has been the purpose of our AI discussion series that I have organised for the members of the AI Centre, especially for those on our Foundational AI CDT.

I kicked off the discussion series with a talk outlining the ongoing debate over whether there is an existential risk from AI “going rogue,” as Yoshua Bengio has put it. By this I mean a risk of humanity as a whole losing control over powerful AI systems. While this sounds like science fiction at first blush, it is fair to say that this debate is far from settled in the AI research community. There are very strong feelings on both sides, and if we are to cooperate as a community in mitigating risks from AI, it is urgent that we form a consensus on what these risks are. By presenting the arguments from both sides in a neutral way, I hope I have done a small amount to help those on both ends of the spectrum understand each other. You can watch my talk here: https://www.youtube.com/watch?v=PI9OXHPyN8M

Ivan Vegner, PhD student in NLP at the University of Edinburgh, was kind enough to travel down for our second talk, on properties of agents in general, both biological and artificial. He argued that sufficiently agentic AI systems, if created, would pose serious risks to humanity, because they may pursue sub-goals such as seeking power and influence or increasing their resistance to being switched off—after all, almost any goal is easier to pursue if you have power and cannot be switched off! Stuart Russell pithily puts this as “You can’t fetch the coffee if you’re dead.” Ivan is an incredibly lucid speaker. You can see his talk Human-like in Every way? here https://www.youtube.com/watch?v=LGeOMA25Xvc

For some, a crux in this existential risk question might be whether AI systems will think like us, or in some alien way. Perhaps we can more easily keep AI systems under control if we can create them in our own image? Or could this backfire—could we end up with systems that have the understanding to deceive or manipulate? Professors Chris Watkins and Nello Christianini dug into this question for us by debating the motion “We can expect machines to eventually think in a human-like way.” (Chris for, Nello against). There were many, many questions afterwards, and Chris and Nello very kindly stayed around to continue the conversation. Watch the debate here: https://www.youtube.com/watch?v=zWCUHmIdWhE

Separate from all of this is the question of misuse. Many technologies are dual-use, but their downsides can be successfully limited through regulation. With AI it is different: the scale can be enormous and rapidly increased (often the bottleneck is simply buying/renting more GPUs), there is a culture of immediately open-sourcing software so that anyone can use it, and AI models often require very little expertise to run or adapt to new use-cases. Professor Mirco Musolesi outlined a number of risks he perceives from using AI systems to autonomously make decisions in economics, geo-politics, and warfare. His talk was incredibly thought-provoking: You can see his talk here: https://youtu.be/QH9eYPglgt8

This series has helped foster an ongoing conversation in the AI Centre on the risks of AI and how we can potentially steer around them. Suffice to say it is a minefield.

We should certainly not forget the incredible potential of AI to have a positive impact on society, from automated and personalised medicine, to the acceleration of scientific and technological advancements aimed at mitigating climate change. But there is no shortage of perceived risks, and currently a disconcerting lack of technical and political strategies to deal with them. Many of us at the AI Centre are deeply worried about where we are going. Many of us are optimists. We need to keep talking and increase our common ground.

We’re racing into the future. Let’s hope we get what AI has been promising society for decades. Let’s try and steer ourselves along the way.

 

Reuben Adams is a final year PhD student in the UKRI CDT in Foundational AI.

“Safe Trajectory Sampling in Model-based Reinforcement Learning for Robotic Systems” By Sicelukwanda Zwane

By sharon.betts, on 29 September 2023

In the exciting realm of Model-based Reinforcement Learning (MBRL), researchers are constantly pushing the boundaries of what robots can learn to achieve when given access to an internal model of the environment. One key challenge in this field is ensuring that robots can perform tasks safely and reliably, especially in situations where they lack prior data or knowledge about the environment. That’s where the work of Sicelukwanda Zwane comes into play.

Background

In MBRL, robots use small sets of data to learn a dynamics model. This model is like a crystal ball that predicts how the system will respond to a given sequence of different actions. With MBRL, we can train policies from simulated trajectories sampled from the dynamics model instead of first generating them by executing each action on the actual system, a process that can take extremely long periods of time on a physical robot and possibly cause wear and tear.

One of the tools often used in MBRL is the Gaussian process (GP) dynamics model. GPs are fully-Bayesian models that not only model the system but also account for the uncertainty in state observations. Additionally, they are flexible and are able to learn without making strong assumptions about the underlying system dynamics [1].

The Challenge of Learning Safely

When we train robots to perform tasks, it’s not enough to just predict what will happen; we need to do it safely. As with most model classes in MBRL, GPs don’t naturally incorporate safety constraints. This means that they may produce unsafe or unfeasible trajectories. This is particularly true during early stages of learning, when the model hasn’t seen much data, it can produce unsafe and seemingly random trajectories.

For a 7 degree of freedom (DOF) manipulator robot, bad trajectories may contain self-collisions.

 

Distributional Trajectory Sampling

In standard GP dynamics models, the posterior is represented in distributional form – using its parameters, the mean vector and covariance matrix. In this form, it is difficult to reason about

about the safety of entire trajectories. This is because trajectories are generated through iterative random sampling. Furthermore, this kind of trajectory sampling is limited to cases where the intermediate state marginal distributions are Gaussian distributed.

Pathwise Trajectory Sampling

Zwane uses an innovative alternative called “pathwise sampling” [3]. This approach draws samples from GP posteriors using an efficient method called Matheron’s rule. The result is a set of smooth, deterministic trajectories that aren’t confined to Gaussian distributions and are temporally correlated.

Adding Safety

The beauty of pathwise sampling [3] is that it has a particle representation of the GP posterior, where individual trajectories are smooth, differentiable, and deterministic functions. This allows for the isolation of constraint-violating trajectories from safe ones. For safety, rejection sampling is performed on trajectories that violate safety constraints, leaving behind only the safe ones to train the policy. Additionally, soft constraint penalty terms are added to the reward function.

Sim-Real Robot Experiments

To put this approach to the test, Zwane conducted experiments involving a 7-DoF robot arm in a simulated constrained reaching task, where the robot has to avoid colliding with a low ceiling. The method successfully learned a reaching policy that adhered to safety constraints, even when starting from random initial states.

In this constrained manipulation task, the robot is able to reach the goal (shown by the red sphere – bottom row) without colliding with the ceiling (blue – bottom row) using less than 100 seconds of data in simulation.

Summary

Sicelukwanda Zwane’s research makes incremental advances on the safety of simulated trajectories by incorporating safety constraints while keeping the benefits of using fully-Bayesian dynamics models such as GPs. This method promises to take MBRL out of simulated environments and make it more applicable to real-world settings. If you’re interested in this work, we invite you to dive into the full paper, published at the recent IEEE CASE 2023 conference.

References

 

  1. M. P. Deisenroth and C. E. Rasmussen. PILCO: A Model-based and Data-efficient Approach to Policy Search. ICML, 2011.
  2. S. Kamthe and M. P. Deisenroth. Data-Efficient Reinforcement Learning with Probabilistic Model Predictive Control. AISTATS, 2018.
  3. J. T. Wilson, V. Borovitskiy, A. Terenin, P. Mostowsky, and M. P. Deisenroth. Pathwise Conditioning of Gaussian Processes. JMLR, 2021.

 

Student-Led Workshop – Distance-based Methods in Machine Learning – Review by Masha Naslidnyk

By sharon.betts, on 3 July 2023

We are delighted to announce the successful conclusion of our recent workshop on Distance-based Methods in Machine Learning. Held at the historical Bentham House on 27-28th of June, the event brought together approximately 60 delegates, including leading experts and researchers from statistics and machine learning.The workshop showcased a diverse range of speakers who shared their knowledge and insights on the theory and methodology behind machine learning approaches utilising kernel-based and Wasserstein distances. Topics covered included parameter estimation, generalised Bayes, hypothesis testing, optimal transport, optimization, and more.The interactive sessions and engaging discussions created a vibrant learning environment, fostering networking opportunities and collaborations among participants. We extend our gratitude to the organising committee, speakers, and attendees for their valuable contributions to this successful event. Stay tuned for future updates on similar initiatives as we continue to explore the exciting possibilities offered by distance-based methods in machine learning.

A large group of attendees for the workshop stand in front of a screen, smiling at the camera.

Happy attendees at the Distance-based learning workshop

Conferences and Workshops – GOFCP, MLF & EDS 2022 – Recap of events by Antonin Schrab

By sharon.betts, on 16 November 2022

In September 2022 I had the amazing opportunity to participate in workshops in Rennes and in Sophia Antipolis, and in a doctoral symposium in Alicante!

In poster sessions and talks, I have presented my work on Aggregated Kernel Tests which covers three of my papers. The first one is MMD Aggregated Two-Sample Test where the two-sample problem is considered, in which one has access to samples from two distributions and is interested in detecting whether those come from the same or from different distributions. The second is KSD Aggregated Goodness-of-fit Test in which we consider the goodness-of-fit problem where one is given some samples and is asked whether these come from a given model (with access to its density or score function). In the third one, Efficient Aggregated Kernel Tests using Incomplete U-statistics, we propose computationally efficient tests for the two-sample, goodness-of-fit, and independence problems; this last one consists in detecting dependence between the two components of paired samples. We tackle these three testing problems using kernel-based statistics, in such a setting the performance of these tests is known to heavily depend on the choice of kernels or kernel parameters (i.e. bandwidth parameter). We propose tests which aggregate over a collection of kernels and retain test power, we theoretically prove optimality of our tests under some regularity assumptions, and empirically show that our aggregated tests outperform other state-of-the-art kernel-based tests.

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I started the month of September by participating in GOFCP 2022, the 5th Workshop on Goodness-of-Fit, Change-Point and related problems, from 2nd to 4th September in ENSAI in Rennes (France). It was extremely interesting to hear about the latest research in this very specific research field which covers exactly the topics I had been working on since the start of my PhD.

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I then went to EURECOM in Sophia Antipolis (France) for MLF 2022, the ELISE Theory Workshop on Machine Learning Fundamentals, from 5th to 7th September. Talks and poster sessions covered the theory of kernel methods, hypothesis testing, partial differential equations, optimisation, Gaussian processes, explainability and AI safety.

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Finally, I participated in EDS 2022, the ELLIS Doctoral Symposium 2022, hosted by the ELLIS Alicante at the University of Alicante in Spain from 19th to 23rd September. It was an amazing experience to meet so many other PhD students working on diverse topics in Machine Learning. I especially enjoyed the numerous poster sessions which allowed to engage with other students and discuss their current research!

I am extremely grateful to Valentin PatileaMotonobu Kanagawa and Aditya Gulati for the respective invitations, and to my CDT (UCL CDT in Foundational AI with funding from UKRI) which allowed me to participate in those workshops/symposium!

CDT Students shine at poster showcase event

By sharon.betts, on 4 November 2022

Tuesday 1st November was a busy day at the CDT and UCL Centre for Artificial Intelligence with our joint UKRI CDT poster showcase and AI demo event. Together with the UKRI CDT in AI-Enabled Healthcare we put on an event featuring posters, demos, AI art and robots.

David Barber is at podium presenting his thoughts on the CDT to an audience in the Function Space at 90 High Holborn

Prof David Barber presenting the latest news on the CDT

The afternoon began with presentations by the CDT centre directors Prof David Barber and Prof Paul Taylor, as well as our industry sponsor Ulrich Paquet from Deepmind. In attendance were students, academics and industry partners, keen to understand what we have been doing and where our research will take us in the future.

a student demonstrates his work on a laptop and screen

PhD Candidate Jakob Zeitler provides a demo on screen

We had approximately 40 posters on display, with a further 19 demonstrations of AI by a variety of groups from Vision to Natural Language Processing. Engagement with the poster presenters was high across the board and a wonderful opportunity for our students to engage with others about the work that they have undertaken the last few years.

A student presents his poster to a crowd of interested listeners

PhD candidate Reuben Adams presents his poster to a crowd of attendees

We were honoured to have the Provost in attendance to witness just how vibrant and stimulating our centres are as part of a dynamic and successful Computer Science department.

Provost Dr Michael Spence stands in front of AI generated artwork with David Barber and crowd in attendance

Provost Dr Michael Spence unveils the Amedeo Modigliani painting

The UCL Centre of Artificial Intelligence have been donated a rare 3D generated AI generated painting of a Amedeo Modigliani, which started as a Masters and then PhD project for Dr. Anthony Bouchard and Dr. George Cann and will be displayed at the AI Centre for all to see.

The day ended with a robot display in the Function Space, showcasing the quadrapod robots that our students are working with both at the AI Centre and the soon to be opened UCL East.

Two quadrapod robots on display

Two quadrapod robots being demonstrated to the crowd

It was wonderful to witness all the different ways in which AI is being applied and developed to help solve some of societies greatest needs and to have the opportunity to share the work of our students with a wider audience.

With thanks to those who attended, our students, director David Barber, AI Centre manager Sarah Bentley and the TSG team for their time, patience and support in helping to make this a hugely successful event.