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Deep learning techniques teach neural model to 'play' retrosynthesis
Researchers, from biochemists to material scientists, have long relied on the rich variety of organic molecules to solve pressing challenges. Some molecules may be useful in treating diseases, others for lighting our digital displays, still others for pigments, paints, and plastics. The unique properties of each molecule are determined by its structure--that is, by the connectivity of its constituent atoms. Once a promising structure is identified, there remains the difficult task of making the targeted molecule through a sequence of chemical reactions. Organic chemists generally work backwards from the target molecule to the starting materials using a process called retrosynthetic analysis.
Artificial Intelligence firm Biovista repositions four promising therapeutics against COVID-19
Biovista, a privately-held AI / bioscience firm best known for drug repositioning, has identified four treatments – two prescription drugs and two over-the-counter compounds -- to counter key symptoms of COVID-19. "Drug AI helps find that needle in the haystack, and we are optimistic that we have found four of them to start," said Aris Persidis, Biovista's President and Co-Founder. The first drug has the potential to reduce viral replication, limit inflammatory events, and help protect against acute lung injury. The second drug has the potential to reduce viral load, improving the primary ARDS component of the disease and reducing the cytokine storm in COVID-19. "These compounds won't cure COVID-19, but appear able, based on their mechanism of action, to limit the damage," said Dr. Eftychia Lekka, Senior Investigator, Drug Discovery.
MIT work raises a question: Can robots be teammates with humans rather than slaves? ZDNet
The image that most of society has of robots is that of slaves -- creations that can be forced do what humans want. Researchers at the Massachusetts Institute of Technology have formed an interesting take on the robot question that is less about slavery, more about cooperation. They observed that language is a function of humans cooperating on tasks, and imagined how robots might use language when working with humans to achieve some result. The word "team" is a word used prominently way up top in the paper, "Decision-Making for Bidirectional Communication in Sequential Human-Robot Collaborative Tasks," written by scientists Vaibhav V. Unhelkar, Shen Li, and Julie A. Shah of the Computer Science and AI Laboratories at MIT and posted on the MIT Web site on March 31st. The use of the word "team" is significant given the structure of the experiment the scientists designed.
AI lets you be Albert Einstein or the Mona Lisa on all your Zoom calls
Customised video conferencing backgrounds have gotten an artificially intelligent upgrade: real-time animated deepfakes that transform your face into that of a celebrity. Karim Iskakov at the Skolkovo Institute of Science and Technology in Moscow, and Ali Aliev, a software developer in Moscow, have developed a program that lets you create deepfakes in real time during video calls. The program, called Avatarify, works with video conferencing applications such as Zoom or Skype. All it requires is a headshot of the person you want to appear to be. Demonstrating to New Scientist via a Zoom call, Aliev used the program to appear to be speaking as several figures including Boris Johnson, Donald Trump, Albert Einstein and the Mona Lisa.
Model-Based Meta-Reinforcement Learning for Flight with Suspended Payloads
Belkhale, Suneel, Li, Rachel, Kahn, Gregory, McAllister, Rowan, Calandra, Roberto, Levine, Sergey
Transporting suspended payloads is challenging for autonomous aerial vehicles because the payload can cause significant and unpredictable changes to the robot's dynamics. These changes can lead to suboptimal flight performance or even catastrophic failure. Although adaptive control and learning-based methods can in principle adapt to changes in these hybrid robot-payload systems, rapid mid-flight adaptation to payloads that have a priori unknown physical properties remains an open problem. We propose a meta-learning approach that "learns how to learn" models of altered dynamics within seconds of post-connection flight data. Our experiments demonstrate that our online adaptation approach outperforms non-adaptive methods on a series of challenging suspended payload transportation tasks. Videos and other supplemental material are available on our website https://sites.google.com/view/meta-rl-for-flight
Chronnet: a network-based model for spatiotemporal data analysis
Ferreira, Leonardo N., Vega-Oliveros, Didier A., Cotacallapa, Moshe, Cardoso, Manoel F., Quiles, Marcos G., Zhao, Liang, Macau, Elbert E. N.
The amount and size of spatiotemporal data sets from different domains have been rapidly increasing in the last years, which demands the development of robust and fast methods to analyze and extract information from them. In this paper, we propose a network-based model for spatiotemporal data analysis called chronnet. It consists of dividing a geometrical space into grid cells represented by nodes connected chronologically. The main goal of this model is to represent consecutive recurrent events between cells with strong links in the network. This representation permits the use of network science and graphing mining tools to extract information from spatiotemporal data. The chronnet construction process is fast, which makes it suitable for large data sets. In this paper, we describe how to use our model considering artificial and real data. For this purpose, we propose an artificial spatiotemporal data set generator to show how chronnets capture not just simple statistics, but also frequent patterns, spatial changes, outliers, and spatiotemporal clusters. Additionally, we analyze a real-world data set composed of global fire detections, in which we describe the frequency of fire events, outlier fire detections, and the seasonal activity, using a single chronnet.
High-dimensional macroeconomic forecasting using message passing algorithms
As a response to the increasing linkages between the macroeconomy and the financial sector, as well as the expanding interconnectedness of the global economy, empirical macroeconomic models have increased both in complexity and size. For that reason, estimation of modern models that inform macroeconomic decisions - such as linear and nonlinear versions of dynamic stochastic general equilibrium (DSGE) and vector autoregressive (VAR) models - many times relies on Bayesian inference via powerful Markov chain Monte Carlo (MCMC) methods. 1 However, existing posterior simulation algorithms cannot scale up to very high-dimensions due to the computational inefficiency and the larger numerical error associated with repeated sampling via Monte Carlo; see Angelino et al. (2016) for a thorough review of such computational issues from a machine learning and high-dimensional data perspective. In that respect, while Bayesian inference is a natural probabilistic framework for learning about parameters by utilizing all information in the data likelihood and prior, computational restrictions might make it less suitable for supporting real-time decision-making in very high dimensions. This paper introduces to the econometric literature the framework of factor graphs (Kschischang et al., 2001) for the purpose of designing computationally efficient, and easy to maintain, Bayesian estimation algorithms. The focus is not only on "faster" posterior inference broadly interpreted, but on designing algorithms that have such low complexity that are future-proof and can be used in high-dimensional econometric problems with possibly thousands or millions of coefficients.
Automatic low-bit hybrid quantization of neural networks through meta learning
Wang, Tao, Wang, Junsong, Xu, Chang, Xue, Chao
Model quantization is a widely used technique to compress and accelerate deep neural network (DNN) inference, especially when deploying to edge or IoT devices with limited computation capacity and power consumption budget. The uniform bit width quantization across all the layers is usually sub-optimal and the exploration of hybrid quantization for different layers is vital for efficient deep compression. In this paper, we employ the meta learning method to automatically realize low-bit hybrid quantization of neural networks. A MetaQuantNet, together with a Quantization function, are trained to generate the quantized weights for the target DNN. Then, we apply a genetic algorithm to search the best hybrid quantization policy that meets compression constraints. With the best searched quantization policy, we subsequently retrain or finetune to further improve the performance of the quantized target network. Extensive experiments demonstrate the performance of searched hybrid quantization scheme surpass that of uniform bitwidth counterpart. Compared to the existing reinforcement learning (RL) based hybrid quantization search approach that relies on tedious explorations, our meta learning approach is more efficient and effective for any compression requirements since the MetaQuantNet only needs be trained once.
Deep Learning Classification With Noisy Labels
Sanchez, Guillaume, Guis, Vincente, Marxer, Ricard, Bouchara, Frédéric
Deep Learning systems have shown tremendous accuracy in image classification, at the cost of big image datasets. Collecting such amounts of data can lead to labelling errors in the training set. Indexing multimedia content for retrieval, classification or recommendation can involve tagging or classification based on multiple criteria. In our case, we train face recognition systems for actors identification with a closed set of identities while being exposed to a significant number of perturbators (actors unknown to our database). Face classifiers are known to be sensitive to label noise. We review recent works on how to manage noisy annotations when training deep learning classifiers, independently from our interest in face recognition.
Learning the Language of Software Errors
Chockler, Hana | Kesseli, Pascal (University of Oxford) | Kroening, Daniel (University of Oxford) | Strichman, Ofer (Technion, Israeli Institute of Technology)
We propose to use algorithms for learning deterministic finite automata (DFA), such as Angluin’s L* algorithm, for learning a DFA that describes the possible scenarios under which a given program error occurs. The alphabet of this automaton is given by the user (for instance, a subset of the function call sites or branches), and hence the automaton describes a user-defined abstraction of those scenarios. More generally, the same technique can be used for visualising the behavior of a program or parts thereof. It can also be used for visually comparing different versions of a program (by presenting an automaton for the behavior in the symmetric difference between them), and for assisting in merging several development branches. We present experiments that demonstrate the power of an abstract visual representation of errors and of program segments, accessible via the project’s web page. In addition, our experiments in this paper demonstrate that such automata can be learned efficiently over real-world programs. We also present lazy learning, which is a method for reducing the number of membership queries while using L*, and demonstrate its effectiveness on standard benchmarks.