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PAC-Bayesian Reward-Certified Outcome Weighted Learning

arXiv.org Machine Learning

Estimating optimal individualized treatment rules (ITRs) via outcome weighted learning (OWL) often relies on observed rewards that are noisy or optimistic proxies for the true latent utility. Ignoring this reward uncertainty leads to the selection of policies with inflated apparent performance, yet existing OWL frameworks lack the finite-sample guarantees required to systematically embed such uncertainty into the learning objective. To address this issue, we propose PAC-Bayesian Reward-Certified Outcome Weighted Learning (PROWL). Given a one-sided uncertainty certificate, PROWL constructs a conservative reward and a strictly policy-dependent lower bound on the true expected value. Theoretically, we prove an exact certified reduction that transforms robust policy learning into a unified, split-free cost-sensitive classification task. This formulation enables the derivation of a nonasymptotic PAC-Bayes lower bound for randomized ITRs, where we establish that the optimal posterior maximizing this bound is exactly characterized by a general Bayes update. To overcome the learning-rate selection problem inherent in generalized Bayesian inference, we introduce a fully automated, bounds-based calibration procedure, coupled with a Fisher-consistent certified hinge surrogate for efficient optimization. Our experiments demonstrate that PROWL achieves improvements in estimating robust, high-value treatment regimes under severe reward uncertainty compared to standard methods for ITR estimation.


Finding Dino: A plug-and-play framework for unsupervised detection of out-of-distribution objects using prototypes

arXiv.org Artificial Intelligence

Detecting and localising unknown or Out-of-distribution (OOD) objects in any scene can be a challenging task in vision. Particularly, in safety-critical cases involving autonomous systems like automated vehicles or trains. Supervised anomaly segmentation or open-world object detection models depend on training on exhaustively annotated datasets for every domain and still struggle in distinguishing between background and OOD objects. In this work, we present a plug-and-play generalised framework - PRototype-based zero-shot OOD detection Without Labels (PROWL). It is an inference-based method that does not require training on the domain dataset and relies on extracting relevant features from self-supervised pre-trained models. PROWL can be easily adapted to detect OOD objects in any operational design domain by specifying a list of known classes from this domain. PROWL, as an unsupervised method, outperforms other supervised methods trained without auxiliary OOD data on the RoadAnomaly and RoadObstacle datasets provided in SegmentMeIfYouCan (SMIYC) benchmark. We also demonstrate its suitability for other domains such as rail and maritime scenes.


Syntactico-Semantic Reasoning using PCFG, MEBN, and PR-OWL

arXiv.org Artificial Intelligence

Probabilistic context free grammars (PCFG) have been the core of the probabilistic reasoning based parsers for several years especially in the context of the NLP. Multi entity bayesian networks (MEBN) a First Order Logic probabilistic reasoning methodology and is widely adopted and used method for uncertainty reasoning. Further upper ontology like Probabilistic Ontology Web Language (PR-OWL) built using MEBN takes care of probabilistic ontologies which model and capture the uncertainties inherent in the domain's semantic information. The paper attempts to establish a link between probabilistic reasoning in PCFG and MEBN by proposing a formal description of PCFG driven by MEBN leading to usage of PR-OWL modeled ontologies in PCFG parsers.


Mattel's new robot is a pet dinosaur that won't try to eat you

Engadget

Since dinosaurs went extinct 66 million years ago, we've never experienced them as living, breathing animals. We can look at their bones in a museum, or we can watch recreations of them in films like this summer's Jurassic World: Fallen Kingdom. But both those options lack that visceral feel you get from seeing a real creature in a zoo. Though it's unlikely you'll ever live long enough to see a dinosaur in the flesh, you can still pretend to have one as a pet, thanks to Mattel's new Alpha Training Blue robot. She roars, coos and even responds to your commands like her movie inspiration -- but is far less deadly.


The sexist dinosaurs aren't only on the prowl in old media

The Guardian

Last week, Caitlin Jenner and a robot called Sophia talked about what it means to be human and a woman. Yet, while the 60,000-strong audience they addressed at a tech-friendly Web Summit in Lisbon appeared cutting edge, their industry is in danger of inheriting elements of the old industries they consider part of a dinosaur age. Sexism and homophobia in Hollywood, the media and politics has been exposed by recent scandals. It is normally newspapers that are compared to the extinct monsters of the past by Silicon Valley types. One hundred and 98 local newspapers have closed in Britain alone in little over a decade.