stable region
Machine learning approach for mapping the stable orbits around planets
Pinheiro, Tiago F. L. L., Sfair, Rafael, Ramon, Giovana
Numerical N-body simulations are commonly used to explore stability regions around exoplanets, offering insights into the possible existence of satellites and ring systems. This study aims to utilize Machine Learning (ML) techniques to generate predictive maps of stable regions surrounding a hypothetical planet. The approach can also be extended to planet-satellite systems, planetary ring systems, and other similar configurations. A dataset was generated using 10^5 numerical simulations, each incorporating nine orbital features for the planet and a test particle in a star-planet-test particle system. The simulations were classified as stable or unstable based on stability criteria, requiring particles to remain stable over a timespan equivalent to 10,000 orbital periods of the planet. Various ML algorithms were tested and fine-tuned through hyperparameter optimization to determine the most effective predictive model. Tree-based algorithms showed comparable accuracy in performance. The best-performing model, using the Extreme Gradient Boosting (XGBoost) algorithm, achieved an accuracy of 98.48%, with 94% recall and precision for stable particles and 99% for unstable particles. ML algorithms significantly reduce the computational time required for three-body simulations, operating approximately 100,000 times faster than traditional numerical methods. Predictive models can generate entire stability maps in less than a second, compared to the days required by numerical simulations. The results from the trained ML models will be made accessible through a public web interface, enabling broader scientific applications.
- South America > Brazil > São Paulo (0.04)
- Europe > Germany > Baden-Württemberg > Tübingen Region > Tübingen (0.04)
- Europe > United Kingdom > England > Cambridgeshire > Cambridge (0.04)
- Europe > France (0.04)
Characterizing stable regions in the residual stream of LLMs
Janiak, Jett, Karwowski, Jacek, Mangat, Chatrik Singh, Giglemiani, Giorgi, Petrova, Nora, Heimersheim, Stefan
We identify stable regions in the residual stream of Transformers, where the model's output remains insensitive to small activation changes, but exhibits high sensitivity at region boundaries. These regions emerge during training and become more defined as training progresses or model size increases. The regions appear to be much larger than previously studied polytopes. Our analysis suggests that these stable regions align with semantic distinctions, where similar prompts cluster within regions, and activations from the same region lead to similar next token predictions. This work provides a promising research direction for understanding the complexity of neural networks, shedding light on training dynamics, and advancing interpretability.
- North America > United States > New York (0.04)
- Europe > United Kingdom > England > Oxfordshire > Oxford (0.04)
- Asia > Middle East > Israel (0.04)
A critical reappraisal of predicting suicidal ideation using fMRI
Verstynen, Timothy, Kording, Konrad
For many psychiatric disorders, neuroimaging offers a potential for revolutionizing diagnosis and treatment by providing access to preverbal mental processes. In their study "Machine learning of neural representations of suicide and emotion concepts identifies suicidal youth."1, Just and colleagues report that a Naive Bayes classifier, trained on voxelwise fMRI responses in human participants during the presentation of words and concepts related to mortality, can predict whether an individual had reported having suicidal ideations with a classification accuracy of 91%. Here we report a reappraisal of the methods employed by the authors, including re-analysis of the same data set, that calls into question the accuracy of the authors findings.
- North America > United States > Pennsylvania > Allegheny County > Pittsburgh (0.15)
- North America > United States > Pennsylvania > Philadelphia County > Philadelphia (0.15)
- Health & Medicine > Therapeutic Area > Psychiatry/Psychology (1.00)
- Health & Medicine > Health Care Technology (1.00)
- Health & Medicine > Therapeutic Area > Neurology (0.70)