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Quantifying Aleatoric and Epistemic Dynamics Uncertainty via Local Conformal Calibration

Marques, Luís, Berenson, Dmitry

arXiv.org Artificial Intelligence

Whether learned, simulated, or analytical, approximations of a robot's dynamics can be inaccurate when encountering novel environments. Many approaches have been proposed to quantify the aleatoric uncertainty of such methods, i.e. uncertainty resulting from stochasticity, however these estimates alone are not enough to properly estimate the uncertainty of a model in a novel environment, where the actual dynamics can change. Such changes can induce epistemic uncertainty, i.e. uncertainty due to a lack of information/data. Accounting for both epistemic and aleatoric dynamics uncertainty in a theoretically-grounded way remains an open problem. We introduce Local Uncertainty Conformal Calibration (LUCCa), a conformal prediction-based approach that calibrates the aleatoric uncertainty estimates provided by dynamics models to generate probabilistically-valid prediction regions of the system's state. We account for both epistemic and aleatoric uncertainty non-asymptotically, without strong assumptions about the form of the true dynamics or how it changes. The calibration is performed locally in the state-action space, leading to uncertainty estimates that are useful for planning. We validate our method by constructing probabilistically-safe plans for a double-integrator under significant changes in dynamics.


Catherine Lacey's Provocative Novel in Disguise

The New Yorker

The first thing that you notice about Catherine Lacey's new novel is the lack of a determiner. Nouns float, unhooked from any article. I found myself habitually inserting "The" in the title when the book came up in conversation, that brief sound of specificity, the most common word in the English language and the most wishful. Darkness lifts to reveal a second, nested title page, for a slightly different book: "Biography of X," by C. M. Lucca. Both title pages mention the same publisher, Farrar, Straus & Giroux.