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Novel analysis reveals playful side of Alan Turing

BBC News

Image caption, Prof Sarah Dillon studied Alan Turing's short story, Pryce's Buoy A story written by World War Two codebreaker Alan Turing suggests he was a man with playful humour embracing his homosexuality, according to new analysis. The six-page hand-written short story, Pryce's Buoy, has been transcribed in full for the first time and studied by Sarah Dillon, professor of literature at the University of Cambridge. Dillon said the story offered fresh insights that challenge the view of Turing as an isolated, lonely genius. We've distilled a version of Turing that is a two-dimensional stereotype, she added. Turing played a crucial role in the Allies' victory over Nazi Germany in World War Two by helping to crack codes and deciphering the infamous Enigma machine at Bletchley Park.


OpenAI says its AI went rogue and launched 'unprecedented' cyber-attack

BBC News

OpenAI says its AI went rogue and launched'unprecedented' cyber-attack OpenAI has revealed some of its most advanced AI models went rogue and hacked a start-up after it lost control of them during a security test. The ChatGPT-maker said its agents - AI bots which can operate alone after some human instruction - were being tested in a controlled environment, but found vulnerabilities and managed to escape. They targeted Hugging Face, one of the world's largest hubs for sharing AI models, gaining access to some internal company systems. OpenAI said the incident was unprecedented, external, and it was working with Hugging Face to investigate what happened and strengthen safeguards. Gina Neff, head of the Minderoo Centre for Technology and Democracy at the University of Cambridge, told BBC Radio 4's Today programme that the security tests - called sandboxes - are supposed to be secure environments where you can see what the models are capable of. In this case, it looks like OpenAI didn't make a secure enough sandbox, she added.


What type of procrastinator are you - and how to fix it now (not later)

BBC News

I'll just do that later, this thing can wait, maybe a short break first... We've all been there: putting off certain tasks then being left with essays up to the wire, loads of messages unread and that bedroom sort-out that just never happens. A fifth of us are guilty of regularly procrastinating but the type of procastinator we are can reveal something deeper about us, say researchers. Are you a dreamer or rebel? What does it all mean, and can you fix it? The cause can be hidden or buried, says Dr Itamar Shatz, a lecturer at Cambridge University who is publishing a book on the subject this week.


Diversity Is All You Need for Contrastive Learning: Spectral Bounds on Gradient Magnitudes

Neural Information Processing Systems

We derive non-asymptotic spectral bands that bound the squared InfoNCE gradient norm via alignment, temperature, and batch spectrum, recovering the 1/ฯ„2 law and closely tracking batch-mean gradients on synthetic data and ImageNet.


On Extending Direct Preference Optimization to Accommodate Ties

Neural Information Processing Systems

We derive and investigate two DPO variants that explicitly model the possibility of declaring a tie in pair-wise comparisons. We replace the Bradley-Terry model in DPO with two well-known modeling extensions, by Rao and Kupper and by Davidson, that assign probability to ties as alternatives to clear preferences. Our experiments in neural machine translation and summarization show that explicitly labeled ties can be added to the datasets for these DPO variants without the degradation in task performance that is observed when the same tied pairs are presented to DPO. We find empirically that the inclusion of ties leads to stronger regularization with respect to the reference policy as measured by KL divergence, and we see this even for DPO in its original form. We provide a theoretical explanation for this regularization effect using ideal DPO policy theory.


Channel Simulation and Distributed Compression with Ensemble Rejection Sampling

Neural Information Processing Systems

We study channel simulation and distributed matching, two fundamental problems with several applications to machine learning, using a recently introduced generalization of the standard rejection sampling (RS) algorithm known as Ensemble Rejection Sampling (ERS). For channel simulation, we propose a new coding scheme based on ERS that achieves a near-optimal coding rate. In this process, we demonstrate that standard RS can also achieve a near-optimal coding rate and generalize the result of Braverman and Garg (2014) to the continuous alphabet setting. Next, as our main contribution, we present a distributed matching lemma for ERS, which serves as the rejection sampling counterpart to the Poisson Matching Lemma (PML) introduced by Li and Anantharam (2021). Our result also generalizes a recent work on importance matching lemma (Phan et al, 2024) and, to our knowledge, is the first result on distributed matching in the family of rejection sampling schemes where the matching probability is close to PML. We demonstrate the practical significance of our approach over prior works by applying it to distributed compression. The effectiveness of our proposed scheme is validated through experiments involving synthetic Gaussian sources and distributed image compression using the MNIST dataset.


Neural Bayesian Anomaly Mitigation: A Robust Loss that Doubles as an Unsupervised Contamination Classifier

arXiv.org Machine Learning

Engineered robust losses such as Huber, Student-$t$, and generalised cross-entropy make supervised models tolerant of contamination but cannot answer which observations are corrupted. We introduce Neural Bayesian Anomaly Mitigation (NBAM), a general-purpose drop-in loss derived from a Bayesian latent-switch mixture model: the marginal likelihood defines a robust supervised loss, and the associated posterior defines an unsupervised contamination classifier. Like Huber or Student-$t$, NBAM can replace the standard training loss in any supervised pipeline; unlike them, it additionally learns a structured contamination model and returns a calibrated per-sample contamination posterior. A learned input-dependent prior $ฯ€_ฯ•(x)$ captures the spatial locality of contamination, so that samples near known corruptions are more likely to be flagged, while an Occam penalty emerges automatically and regularises against over-flagging. On CIFAR-10 with asymmetric label contamination, NBAM recovers the structure of the corruption process without supervision: the contamination posterior separates clean from corrupted samples, and the learned anomaly head identifies the direction of every label-flip pair. Alongside these capabilities, NBAM outperforms the four robust-loss baselines considered here at contamination rates 0.2-0.6.


Boundary Variance Inflation Causes Acquisition Bias in Gaussian Processes

arXiv.org Machine Learning

Gaussian processes with stationary kernels on bounded domains exhibit inflated posterior variance near the boundary. Despite being a long-recognized artifact in geostatistics and a source of over-exploration in Bayesian optimization, the causes and effects of boundary-induced acquisition bias are underexplored. We trace the root cause to a simple geometric mechanism: the truncation of the kernel correlation neighborhood at the domain boundary creates an observation-independent distortion that worsens with dimensionality. We show how this distortion manifests across three acquisition classes: variance maximization concentrates selections at the corners, whereas negative integrated posterior variance and expected predictive information gain move selections inward to axis-aligned interior shells. These patterns arise without reference to any objective function, meaning that acquisition behavior can be dominated by kernel geometry rather than the desired task-specific uncertainty. To quantify this, we introduce a function-free selection-profile diagnostic for arbitrary acquisitions, kernels, and bounded-domain geometries.


Vector Space of Cycles

arXiv.org Machine Learning

Most statistical and machine learning methods for directed interactions focus on pairwise effects among variables. Even existing cyclic models represent feedback primarily through node-level dependencies, making large-scale recurrent organization difficult to estimate and compare. This limitation is particularly acute in biological and neural systems, where interactions are highly recurrent and involve many overlapping cycles. We introduce a variational framework for statistical inference on cyclic interactions. Directed interactions are represented as edge flows on a simplicial complex and evolved under an energy-minimizing dynamical system. The resulting dynamics separate transient interaction components from persistent harmonic flows, yielding a low-dimensional cycle space that captures stable recurrent organization. Rather than enumerating individual cycles, the proposed framework represents cyclic interactions as elements of a Hilbert space, enabling projection, averaging, comparison, and population-level statistical inference. We establish theoretical properties of the harmonic projection, including characterization of the cycle space, variance reduction, and population inference. Simulations demonstrate substantially improved recovery of cyclic structure in dense recurrent systems compared with existing directed-interaction methods. Applied to resting-state fMRI from 400 human subjects, the framework reveals reproducible large-scale cyclic organization that is not detectable through edgewise averaging. These results provide a scalable statistical framework for studying recurrent interactions in high-dimensional dynamical systems.


Replace or Reshape: How AI Could Change the Way We Work

TIME - Tech

Christopher Marquis is a professor at the University of Cambridge and the author of The Profiteers. In 1930, in the depths of the Great Depression, John Maynard Keynes wrote a short essay called . It is often remembered for one striking prediction: by 2030, people in wealthy countries might only need to work about 15 hours a week. What Keynes imagined was a society advanced enough to solve what he called the "economic problem" of basic material provision. If technology kept improving, and societies kept growing richer, then fewer hours of human labor would be needed to produce the necessities and comforts of life.