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Ship sinks in new drone attack off Bulgaria, PM summons Russian ambassador
Image caption, Five crew members on the Ukrainian-registered merchant ship suffered minor injuries in Tuesday's attacks A merchant ship has sunk after drones hit two vessels off Bulgaria's Black Sea coast, Prime Minister Rumen Radev has said. He indicated Russia was suspected of the attacks and that he had called in its ambassador. One of the ships went down 17 nautical miles (31km) east of Krapets and one crew member was saved, he said. The other, Ukrainian-owned vessel was hit by three drones 18 nautical miles from the town of Byala and all 15 crew were rescued, he added. The drone attacks come a week after two other commercial ships were hit by sea and aerial drones in Bulgaria's exclusive economic zone.
Drone attack sinks ship off Bulgaria's Black Sea coast, PM says
Is the war entering a new phase? Drone attack sinks ship off Bulgaria's Black Sea coast, PM says Share Drone attack sinks ship off Bulgaria's Black Sea coast, PM says on social media Two ships have been hit in drone attacks off Bulgaria's Black Sea coast, with one of them sinking, Prime Minister Rumen Radev said. The Ukrainian-owned Chelsea 3, which was sailing under a Maltese flag, was hit by three drones and damaged about 18 nautical miles (33km) off Bulgaria at about 1:30am on Tuesday (22:30 GMT on Monday), Radev said. Five crew members received medical assistance, and no one was seriously injured. He added that one crew member from the ship that sank was also rescued.
Bulgaria searches for missing crew after drones hit two ships in Black Sea
Is the war entering a new phase? Bulgarian Prime Minister Rumen Radev says drones have hit two commercial vessels, sinking one ship and wounding several people, in what he denounced as an "absolutely unacceptable" attack. Speaking to reporters on Tuesday, Radev said the ships were attacked by sea drones and aerial drones at about 3am (00:00 GMT), about 70 nautical miles (130km) off Bulgaria's coast, amid a rise in attacks on Black Sea shipping due to expanding drone attacks related to the Russia-Ukraine war. It is a blatant violation of international law and maritime law," Radev said. The Togo-flagged Alfa Watan suffered critical structural damage and sank at the scene.
Ship sinks and crew missing after Black Sea drone attack
A civilian cargo ship has sunk and its crew is missing after being attacked by drones in the Black Sea, Bulgarian officials say. A second vessel - carrying grain - was also hit within Bulgaria's exclusive economic zone, Prime Minister Rumen Radev said. Its 18 crew were rescued. Radev did not say who was behind the attacks, which come as Russia intensifies strikes in the Black Sea, particularly the eastern side, as part of its war against Ukraine. Moscow has not commented on the latest incident, a day after it was accused by Ukrainian President Volodymyr Zelensky of striking a civilian vessel carrying corn.
A Deep Learning Method for Comparing Bayesian Hierarchical Models
Elsemรผller, Lasse, Schnuerch, Martin, Bรผrkner, Paul-Christian, Radev, Stefan T.
Bayesian model comparison (BMC) offers a principled approach for assessing the relative merits of competing computational models and propagating uncertainty into model selection decisions. However, BMC is often intractable for the popular class of hierarchical models due to their high-dimensional nested parameter structure. To address this intractability, we propose a deep learning method for performing BMC on any set of hierarchical models which can be instantiated as probabilistic programs. Since our method enables amortized inference, it allows efficient re-estimation of posterior model probabilities and fast performance validation prior to any real-data application. In a series of extensive validation studies, we benchmark the performance of our method against the state-of-the-art bridge sampling method and demonstrate excellent amortized inference across all BMC settings. We then showcase our method by comparing four hierarchical evidence accumulation models that have previously been deemed intractable for BMC due to partly implicit likelihoods. Additionally, we demonstrate how transfer learning can be leveraged to enhance training efficiency. We provide reproducible code for all analyses and an open-source implementation of our method.
BayesFlow: Amortized Bayesian Workflows With Neural Networks
Radev, Stefan T, Schmitt, Marvin, Schumacher, Lukas, Elsemรผller, Lasse, Pratz, Valentin, Schรคlte, Yannik, Kรถthe, Ullrich, Bรผrkner, Paul-Christian
Modern Bayesian inference involves a mixture of computational techniques for estimating, validating, and drawing conclusions from probabilistic models as part of principled workflows for data analysis (Bรผrkner et al., 2022; Gelman et al., 2020; Schad et al., 2021). Typical problems in Bayesian workflows are the approximation of intractable posterior distributions for diverse model types and the comparison of competing models of the same process in terms of their complexity and predictive performance. However, despite their theoretical appeal and utility, the practical execution of Bayesian workflows is often limited by computational bottlenecks: Obtaining even a single posterior may already take a long time, such that repeated estimation for the purpose of model validation or calibration becomes completely infeasible. BayesFlow provides a framework for simulation-based training of established neural network architectures, such as transformers (Vaswani et al., 2017) and normalizing flows (Papamakarios et al., 2021), for amortized data compression and inference. Amortized Bayesian inference (ABI), as implemented in BayesFlow, enables users to train custom neural networks on model simulations and re-use these networks for any subsequent application of the models. Since the trained networks can perform inference almost instantaneously (typically well below one second), the upfront neural network training is quickly amortized. For instance, amortized inference allows us to test a model's ability to recover its parameters (Schad et al., 2021) or assess its simulation-based calibration (Sรคilynoja et al., 2022; Talts et al., 2018) for different data set sizes in a matter of seconds, even though this may require the estimation of thousands of posterior distributions. BayesFlow offers a user-friendly API, which encapsulates the details of neural network architectures and training procedures that are less relevant for the practitioner and provides robust default implementations that work well across many applications. At the same time, BayesFlow implements a modular software architecture, allowing machine learning scientists to modify every component of the pipeline for custom applications as well as research at the frontier of Bayesian inference.
Amortized Bayesian Inference for Models of Cognition
Radev, Stefan T., Voss, Andreas, Wieschen, Eva Marie, Bรผrkner, Paul-Christian
As models of cognition grow in complexity and number of parameters, Bayesian inference with standard methods can become intractable, especially when the data-generating model is of unknown analytic form. Recent advances in simulation-based inference using specialized neural network architectures circumvent many previous problems of approximate Bayesian computation. Moreover, due to the properties of these special neural network estimators, the effort of training the networks via simulations amortizes over subsequent evaluations which can re-use the same network for multiple datasets and across multiple researchers. However, these methods have been largely underutilized in cognitive science and psychology so far, even though they are well suited for tackling a wide variety of modeling problems. With this work, we provide a general introduction to amortized Bayesian parameter estimation and model comparison and demonstrate the applicability of the proposed methods on a well-known class of intractable response-time models.
What Data Science Can Tell Us About Our World
A daylong conference will cover a wide-range of topics related to computational data analysis, from how languages spread to ways of improving the value of crowdsourcing. The Data Science Workshop on Computational Social Science takes place Oct. 20. It's the first of what Dragomir Radev, the A. Bartlett Giamatti Professor of Computer Science, expects will be a regular event. "We decided we should try to cover different areas of data science," said Radev, one of the event's organizers. "We're starting with computational social science first and then switch to other areas in which data science and computer science have made an impact, for example, digital humanities, medicine, finance, etc." Radev said the event is something that likely would not have happened 10 or even five years ago.
Generating Extractive Summaries of Scientific Paradigms
Qazvinian, V., Radev, D. R., Mohammad, S. M., Dorr, B., Zajic, D., Whidby, M., Moon, T.
Researchers and scientists increasingly find themselves in the position of having to quickly understand large amounts of technical material. Our goal is to effectively serve this need by using bibliometric text mining and summarization techniques to generate summaries of scientific literature. We show how we can use citations to produce automatically generated, readily consumable, technical extractive summaries. We first propose C-LexRank, a model for summarizing single scientific articles based on citations, which employs community detection and extracts salient information-rich sentences. Next, we further extend our experiments to summarize a set of papers, which cover the same scientific topic. We generate extractive summaries of a set of Question Answering (QA) and Dependency Parsing (DP) papers, their abstracts, and their citation sentences and show that citations have unique information amenable to creating a summary.
Networks and Natural Language Processing
Radev, Dragomir R. (University of Michigan) | Mihalcea, Rada (University of North Texas)
Over the last few years, a number of areas of natural language processing have begun applying graph-based techniques. These include, among others, text summarization, syntactic parsing, word-sense disambiguation, ontology construction, sentiment and subjectivity analysis, and text clustering. In this paper, we present some of the most successful graph-based representations and algorithms used in language processing and try to explain how and why they work.