Atlantic Ocean
Planar Modeling and Sim-to-Real of a Tethered Multimaterial Soft Swimmer Driven by Peano-HASELs
Gravert, Stephan-Daniel, Michelis, Mike Y., Rogler, Simon, Tscholl, Dario, Buchner, Thomas, Katzschmann, Robert K.
Soft robotics has the potential to revolutionize robotic locomotion, in particular, soft robotic swimmers offer a minimally invasive and adaptive solution to explore and preserve our oceans. Unfortunately, current soft robotic swimmers are vastly inferior to evolved biological swimmers, especially in terms of controllability, efficiency, maneuverability, and longevity. Additionally, the tedious iterative fabrication and empirical testing required to design soft robots has hindered their optimization. In this work, we tackle this challenge by providing an efficient and straightforward pipeline for designing and fabricating soft robotic swimmers equipped with electrostatic actuation. We streamline the process to allow for rapid additive manufacturing, and show how a differentiable simulation can be used to match a simplified model to the real deformation of a robotic swimmer. We perform several experiments with the fabricated swimmer by varying the voltage and actuation frequency of the swimmer's antagonistic muscles. We show how the voltage and frequency vary the locomotion speed of the swimmer while moving in liquid oil and observe a clear optimum in forward swimming speed. The differentiable simulation model we propose has various downstream applications, such as control and shape optimization of the swimmer; optimization results can be directly mapped back to the real robot through our sim-to-real matching.
Stunning drone footage shows three killer whales hunt 9-foot great white shark and eat its liver
It is a gripping scene of an orca viciously ripping out the liver of a nine-foot-long great white shark, as two other killer whales excitedly watch the once blue waters of South Africa's Mossel Bay turn blood red before the shark sinks to a the bottom of the sea – never to be seen again. The wild story was captured by a drone camera soaring above and now gives scientists a better understanding about why these apex-predators seem to be fleeing from this regions that was once the shark capital of the world. Orcas are known to feast on a great white shark liver, as to organ is are large, fatty and has become the whale's favorite dish – eight shark carcasses washing ashore the Western Cape in 2017 and all were missing their liver. The footage is part of marine biologist Alison Towner's long-term work with great whites. She shared on her Instagram page that the clip is'one of the most incredible pieces of natural history ever captured on film. The clip which is the first to show an orca eating a great white, is set to air on Discovery's Shark House Thursday night at 9pm ET, which is a day before the highly anticipated Shark Week begins.
A Generative Deep Learning Approach to Stochastic Downscaling of Precipitation Forecasts
Harris, Lucy, McRae, Andrew T. T., Chantry, Matthew, Dueben, Peter D., Palmer, Tim N.
Despite continuous improvements, precipitation forecasts are still not as accurate and reliable as those of other meteorological variables. A major contributing factor to this is that several key processes affecting precipitation distribution and intensity occur below the resolved scale of global weather models. Generative adversarial networks (GANs) have been demonstrated by the computer vision community to be successful at super-resolution problems, i.e., learning to add fine-scale structure to coarse images. Leinonen et al. (2020) previously applied a GAN to produce ensembles of reconstructed high-resolution atmospheric fields, given coarsened input data. In this paper, we demonstrate this approach can be extended to the more challenging problem of increasing the accuracy and resolution of comparatively low-resolution input from a weather forecasting model, using high-resolution radar measurements as a "ground truth". The neural network must learn to add resolution and structure whilst accounting for non-negligible forecast error. We show that GANs and VAE-GANs can match the statistical properties of state-of-the-art pointwise post-processing methods whilst creating high-resolution, spatially coherent precipitation maps. Our model compares favourably to the best existing downscaling methods in both pixel-wise and pooled CRPS scores, power spectrum information and rank histograms (used to assess calibration). We test our models and show that they perform in a range of scenarios, including heavy rainfall.
RangL: A Reinforcement Learning Competition Platform
Zobernig, Viktor, Saldanha, Richard A., He, Jinke, van der Sar, Erica, van Doorn, Jasper, Hua, Jia-Chen, Mason, Lachlan R., Czechowski, Aleksander, Indjic, Drago, Kosmala, Tomasz, Zocca, Alessandro, Bhulai, Sandjai, Arvizu, Jorge Montalvo, Klöckl, Claude, Moriarty, John
The RangL project hosted by The Alan Turing Institute aims to encourage the wider uptake of reinforcement learning by supporting competitions relating to real-world dynamic decision problems. This article describes the reusable code repository developed by the RangL team and deployed for the 2022 Pathways to Net Zero Challenge, supported by the UK Net Zero Technology Centre. The winning solutions to this particular Challenge seek to optimize the UK's energy transition policy to net zero carbon emissions by 2050. The RangL repository includes an OpenAI Gym reinforcement learning environment and code that supports both submission to, and evaluation in, a remote instance of the open source EvalAI platform as well as all winning learning agent strategies. The repository is an illustrative example of RangL's capability to provide a reusable structure for future challenges.
Natural History Museum researchers find 39 potential new species at bottom of ocean using robot
Think you know what lurks beneath you when you take a dip in the ocean? Scientists have discovered 39 species that are'potentially new to science', while exploring up to 16,700 feet (5,100 metres) underwater. A robot was sent down to the abyssal plains of the Clarion-Clipperton Zone (CCZ) in the central Pacific Ocean - one of the least explored regions of the world - to collect specimens of deep sea creatures. The researchers, from the Natural History Museum in London, recovered 39 brand new species of megafauna as well as nine known species. Amongst those found were spindly starfish, tulip-shaped sea sponges, prickly urchins and'gummy squirrel' sea cucumbers.
Relaxed Gaussian process interpolation: a goal-oriented approach to Bayesian optimization
Petit, Sébastien J, Bect, Julien, Vazquez, Emmanuel
This work presents a new procedure for obtaining predictive distributions in the context of Gaussian process (GP) modeling, with a relaxation of the interpolation constraints outside some ranges of interest: the mean of the predictive distributions no longer necessarily interpolates the observed values when they are outside ranges of interest, but are simply constrained to remain outside. This method called relaxed Gaussian process (reGP) interpolation provides better predictive distributions in ranges of interest, especially in cases where a stationarity assumption for the GP model is not appropriate. It can be viewed as a goal-oriented method and becomes particularly interesting in Bayesian optimization, for example, for the minimization of an objective function, where good predictive distributions for low function values are important. When the expected improvement criterion and reGP are used for sequentially choosing evaluation points, the convergence of the resulting optimization algorithm is theoretically guaranteed (provided that the function to be optimized lies in the reproducing kernel Hilbert spaces attached to the known covariance of the underlying Gaussian process). Experiments indicate that using reGP instead of stationary GP models in Bayesian optimization is beneficial.
Dimitris Drandakis of mediastalker on media content security
Dimitris Drandakis: Back in the late '00s, I worked as a software engineer in Athens – Greece. After 10 years in the field, I felt I was coming to a stand-still career so I decided to move to an Ionian Sea island, switching to the tourism industry. That proved to be a wise decision since the economic turbulence hit my country harder than all the rest and tourism was one of the few untouched industries. A few years later when software engineering knocked on my door again with Mediastalker, my heart beat strongly. I put on the CTO cap and the rest is history in the making.
Detecting Volunteer Cotton Plants in a Corn Field with Deep Learning on UAV Remote-Sensing Imagery
Yadav, Pappu Kumar, Thomasson, J. Alex, Hardin, Robert, Searcy, Stephen W., Braga-Neto, Ulisses, Popescu, Sorin C., Martin, Daniel E., Rodriguez, Roberto, Meza, Karem, Enciso, Juan, Diaz, Jorge Solorzano, Wang, Tianyi
The cotton boll weevil, Anthonomus grandis Boheman is a serious pest to the U.S. cotton industry that has cost more than 16 billion USD in damages since it entered the United States from Mexico in the late 1800s. This pest has been nearly eradicated; however, southern part of Texas still faces this issue and is always prone to the pest reinfestation each year due to its sub-tropical climate where cotton plants can grow year-round. Volunteer cotton (VC) plants growing in the fields of inter-seasonal crops, like corn, can serve as hosts to these pests once they reach pin-head square stage (5-6 leaf stage) and therefore need to be detected, located, and destroyed or sprayed . In this paper, we present a study to detect VC plants in a corn field using YOLOv3 on three band aerial images collected by unmanned aircraft system (UAS). The two-fold objectives of this paper were : (i) to determine whether YOLOv3 can be used for VC detection in a corn field using RGB (red, green, and blue) aerial images collected by UAS and (ii) to investigate the behavior of YOLOv3 on images at three different scales (320 x 320, S1; 416 x 416, S2; and 512 x 512, S3 pixels) based on average precision (AP), mean average precision (mAP) and F1-score at 95% confidence level. No significant differences existed for mAP among the three scales, while a significant difference was found for AP between S1 and S3 (p = 0.04) and S2 and S3 (p = 0.02). A significant difference was also found for F1-score between S2 and S3 (p = 0.02). The lack of significant differences of mAP at all the three scales indicated that the trained YOLOv3 model can be used on a computer vision-based remotely piloted aerial application system (RPAAS) for VC detection and spray application in near real-time.
Closing the Loop: A Framework for Trustworthy Machine Learning in Power Systems
Stiasny, Jochen, Chevalier, Samuel, Nellikkath, Rahul, Sævarsson, Brynjar, Chatzivasileiadis, Spyros
Deep decarbonization of the energy sector will require massive penetration of stochastic renewable energy resources and an enormous amount of grid asset coordination; this represents a challenging paradigm for the power system operators who are tasked with maintaining grid stability and security in the face of such changes. With its ability to learn from complex datasets and provide predictive solutions on fast timescales, machine learning (ML) is well-posed to help overcome these challenges as power systems transform in the coming decades. In this work, we outline five key challenges (dataset generation, data pre-processing, model training, model assessment, and model embedding) associated with building trustworthy ML models which learn from physics-based simulation data. We then demonstrate how linking together individual modules, each of which overcomes a respective challenge, at sequential stages in the machine learning pipeline can help enhance the overall performance of the training process. In particular, we implement methods that connect different elements of the learning pipeline through feedback, thus "closing the loop" between model training, performance assessments, and re-training. We demonstrate the effectiveness of this framework, its constituent modules, and its feedback connections by learning the N-1 small-signal stability margin associated with a detailed model of a proposed North Sea Wind Power Hub system.
How do tuna schools associate to dFADs? A study using echo-sounder buoys to identify global patterns
Navarro-García, Manuel, Precioso, Daniel, Gavira-O'Neill, Kathryn, Torres-Barrán, Alberto, Gordo, David, Gallego, Víctor, Gómez-Ullate, David
As fishermen have noticed this behaviour, they have used both natural and man-made floating objects, or drifting Fish Aggregating Devices (dFADs), as a tool for finding and catching tropical tunas. The use of dFADs in tuna purse-seine fisheries has gradually increased since the 1980s to the present time, where vessels using dFADs now contribute to 36% of the world's total tropical tuna catch (Davies et al., 2014; Wain et al., 2021; ISSF, 2021). These widespread changes have highlighted the need to better understand the potential ecological effects of dFADs on tuna ecology and the marine environment, in order to ensure adequate management of fish stocks and dFAD usage. Indeed, both the dynamics of how and why tuna associate to dFADs are still poorly understood. Regarding the reasons behind tuna aggregation to dFADs, a number of hypotheses have been suggested (Fréon and Dagorn, 2000; Dempster and Taquet, 2004; Castro et al., 2002). Of these, two have gained traction: the "meeting-point" hypothesis, which considers that dFADs facilitate the encounter between individuals or schools, thus constituting larger schools that could benefit survival rates (Castro et al., 2002); and the "indicator-log" hypothesis, by which tunas may be safeguarding the survival of their eggs, larvae and juvenile stages by using drifting objects as indicators of areas where plankton and food is readily available (Hall et al., 1992). This scenario has led some authors to postulate that man-made dFADs could have detrimental effects on tuna populations by creating a so-called "ecological trap" which would lead tuna to remain associated to dFADs even as these drift into areas that could negatively affect the tuna's behaviour and biology (Marsac et al., 2000; Hallier and Gaertner, 2008). To the best of our knowledge, there is yet no sufficient evidence to either confirm or reject this hypothesis (see Dagorn et al. (2012) and references therein). Given the concerns around the widespread use of dFADs in tuna fisheries today, it is not surprising that a considerable amount of research has been devoted to characterizing the dynamics at play when tunas aggregate to dFADs.