Crop type maps are frequently generated using remotely sensed data acquired by sensors mounted on satellites, manned aircraft or unmanned aerial vehicles (UAVs or'drones'), the most popular being multispectral sensors mounted on satellites. Aerial multispectral sensors are more frequently employed where imagery with very high spatial resolution is required. However, the use of Lidar data for crop type mapping is still uncommon. This article outlines research done on creating crop type maps using Lidar, Sentinel-2 and aerial data along with several machine learning classification algorithms for differentiating four crop types in an intensively cultivated area. Lidar data is becoming ever-more widely available as more aerial surveys are conducted, UAV-Lidar sensors are becoming more prevalent and Earth observation satellites are being fitted with Lidar sensors.

We've discovered neurons in CLIP that respond to the same concept whether presented literally, symbolically, or conceptually. This may explain CLIP's accuracy in classifying surprising visual renditions of concepts, and is also an important step toward understanding the associations and biases that CLIP and similar models learn. Fifteen years ago, Quiroga et al. discovered that the human brain possesses multimodal neurons. These neurons respond to clusters of abstract concepts centered around a common high-level theme, rather than any specific visual feature. The most famous of these was the "Halle Berry" neuron, a neuron featured in both Scientific American and The New York Times, that responds to photographs, sketches, and the text "Halle Berry" (but not other names).

This article was originally published February 23, 2021 on PSQH by Matt Phillion. An aging population, a shortage of clinicians, and an abundance of data--treating patients grows more and more complicated all the time. Leveraging available and emerging technology to maximize efficiency, however, offers a chance to improve care in innovative ways. "The population is aging, and more and more people are suffering from cardiac issues. Expertise is expensive, and there is limited access to those experts," says Jia Li, co-founder of Cardiologs, a medical technology company developing medical-grade artificial intelligence (AI) and cloud technology to improve cardiac diagnoses.

The Panel Vector Autoregressive (PVAR) model is a popular tool for macroeconomic forecasting and structural analysis in multi-country applications since it allows for spillovers between countries in a very flexible fashion. However, this flexibility means that the number of parameters to be estimated can be enormous leading to over-parameterization concerns. Bayesian global-local shrinkage priors, such as the Horseshoe prior used in this paper, can overcome these concerns, but they require the use of Markov Chain Monte Carlo (MCMC) methods rendering them computationally infeasible in high dimensions. In this paper, we develop computationally efficient Bayesian methods for estimating PVARs using an integrated rotated Gaussian approximation (IRGA). This exploits the fact that whereas own country information is often important in PVARs, information on other countries is often unimportant. Using an IRGA, we split the the posterior into two parts: one involving own country coefficients, the other involving other country coefficients. Fast methods such as approximate message passing or variational Bayes can be used on the latter and, conditional on these, the former are estimated with precision using MCMC methods. In a forecasting exercise involving PVARs with up to $18$ variables for each of $38$ countries, we demonstrate that our methods produce good forecasts quickly.

In this paper we investigate how gradient-based algorithms such as gradient descent, (multi-pass) stochastic gradient descent, its persistent variant, and the Langevin algorithm navigate non-convex losslandscapes and which of them is able to reach the best generalization error at limited sample complexity. We consider the loss landscape of the high-dimensional phase retrieval problem as a prototypical highly non-convex example. We observe that for phase retrieval the stochastic variants of gradient descent are able to reach perfect generalization for regions of control parameters where the gradient descent algorithm is not. We apply dynamical mean-field theory from statistical physics to characterize analytically the full trajectories of these algorithms in their continuous-time limit, with a warm start, and for large system sizes. We further unveil several intriguing properties of the landscape and the algorithms such as that the gradient descent can obtain better generalization properties from less informed initializations.

Welcome to the fourth edition of the AI Index Report. This year we significantly expanded the amount of data available in the report, worked with a broader set of external organizations to calibrate our data, and deepened our connections with the Stanford Institute for Human-Centered Artificial Intelligence (HAI). The AI Index Report tracks, collates, distills, and visualizes data related to artificial intelligence. Its mission is to provide unbiased, rigorously vetted, and globally sourced data for policymakers, researchers, executives, journalists, and the general public to develop intuitions about the complex field of AI. The report aims to be the most credible and authoritative source for data and insights about AI in the world.

This paper investigates the problem of impact-time-control and proposes a learning-based computational guidance algorithm to solve this problem. The proposed guidance algorithm is developed based on a general prediction-correction concept: the exact time-to-go under proportional navigation guidance with realistic aerodynamic characteristics is estimated by a deep neural network and a biased command to nullify the impact time error is developed by utilizing the emerging reinforcement learning techniques. The deep neural network is augmented into the reinforcement learning block to resolve the issue of sparse reward that has been observed in typical reinforcement learning formulation. Extensive numerical simulations are conducted to support the proposed algorithm.

Restless Multi-Armed Bandits (RMABs) have been popularly used to model limited resource allocation problems. Recently, these have been employed for health monitoring and intervention planning problems. However, the existing approaches fail to account for the arrival of new patients and the departure of enrolled patients from a treatment program. To address this challenge, we formulate a streaming bandit (S-RMAB) framework, a generalization of RMABs where heterogeneous arms arrive and leave under possibly random streams. We propose a new and scalable approach to computing index-based solutions. We start by proving that index values decrease for short residual lifetimes, a phenomenon that we call index decay. We then provide algorithms designed to capture index decay without having to solve the costly finite horizon problem, thereby lowering the computational complexity compared to existing methods.We evaluate our approach via simulations run on real-world data obtained from a tuberculosis intervention planning task as well as multiple other synthetic domains. Our algorithms achieve an over 150x speed-up over existing methods in these tasks without loss in performance. These findings are robust across multiple domains.

Translating between languages where certain features are marked morphologically in one but absent or marked contextually in the other is an important test case for machine translation. When translating into English which marks (in)definiteness morphologically, from Yor\`ub\'a which uses bare nouns but marks these features contextually, ambiguities arise. In this work, we perform fine-grained analysis on how an SMT system compares with two NMT systems (BiLSTM and Transformer) when translating bare nouns in Yor\`ub\'a into English. We investigate how the systems what extent they identify BNs, correctly translate them, and compare with human translation patterns. We also analyze the type of errors each model makes and provide a linguistic description of these errors. We glean insights for evaluating model performance in low-resource settings. In translating bare nouns, our results show the transformer model outperforms the SMT and BiLSTM models for 4 categories, the BiLSTM outperforms the SMT model for 3 categories while the SMT outperforms the NMT models for 1 category.

DUBAI, United Arab Emirates (AP) -- A pair of B-52 bombers flew over the Mideast on Sunday, the latest such mission in the region aimed at warning Iran amid tensions between Washington and Tehran. The flight by the two heavy bombers came as a pro-Iran satellite channel based in Beirut broadcast Iranian military drone footage of an Israeli ship hit by a mysterious explosion only days earlier in the Mideast. While the channel sought to say Iran wasn't involved, Israel has blamed Tehran for what it described as an attack on the vessel. The U.S. military's Central Command said the two B-52s flew over the region accompanied by military aircraft from nations including Israel, Saudi Arabia and Qatar. It marked the fourth-such bomber deployment into the Mideast this year and the second under President Joe Biden.