Energy
Physics-informed neural networks for PDE-constrained optimization and control
Barry-Straume, Jostein, Sarshar, Arash, Popov, Andrey A., Sandu, Adrian
A fundamental problem in science and engineering is designing optimal control policies that steer a given system towards a desired outcome. This work proposes Control Physics-Informed Neural Networks (Control PINNs) that simultaneously solve for a given system state, and for the optimal control signal, in a one-stage framework that conforms to the underlying physical laws. Prior approaches use a two-stage framework that first models and then controls a system in sequential order. In contrast, a Control PINN incorporates the required optimality conditions in its architecture and in its loss function. The success of Control PINNs is demonstrated by solving the following open-loop optimal control problems: (i) an analytical problem, (ii) a one-dimensional heat equation, and (iii) a two-dimensional predator-prey problem.
A Multi-Modal Wildfire Prediction and Personalized Early-Warning System Based on a Novel Machine Learning Framework
Wildfires are increasingly impacting the environment, human health and safety. Among the top 20 California wildfires, those in 2020-2021 burned more acres than the last century combined. California's 2018 wildfire season caused damages of $148.5 billion. Among millions of impacted people, those living with disabilities (around 15% of the world population) are disproportionately impacted due to inadequate means of alerts. In this project, a multi-modal wildfire prediction and personalized early warning system has been developed based on an advanced machine learning architecture. Sensor data from the Environmental Protection Agency and historical wildfire data from 2012 to 2018 have been compiled to establish a comprehensive wildfire database, the largest of its kind. Next, a novel U-Convolutional-LSTM (Long Short-Term Memory) neural network was designed with a special architecture for extracting key spatial and temporal features from contiguous environmental parameters indicative of impending wildfires. Environmental and meteorological factors were incorporated into the database and classified as leading indicators and trailing indicators, correlated to risks of wildfire conception and propagation respectively. Additionally, geological data was used to provide better wildfire risk assessment. This novel spatio-temporal neural network achieved >97% accuracy vs. around 76% using traditional convolutional neural networks, successfully predicting 2018's five most devastating wildfires 5-14 days in advance. Finally, a personalized early warning system, tailored to individuals with sensory disabilities or respiratory exacerbation conditions, was proposed. This technique would enable fire departments to anticipate and prevent wildfires before they strike and provide early warnings for at-risk individuals for better preparation, thereby saving lives and reducing economic damages.
KDD CUP 2022 Wind Power Forecasting Team 88VIP Solution
Lin, Fangquan, Jiang, Wei, Zhang, Hanwei, Yang, Cheng
KDD CUP 2022 proposes a time-series forecasting task on spatial dynamic wind power dataset, in which the participants are required to predict the future generation given the historical context factors. The evaluation metrics contain RMSE and MAE. This paper describes the solution of Team 88VIP, which mainly comprises two types of models: a gradient boosting decision tree to memorize the basic data patterns and a recurrent neural network to capture the deep and latent probabilistic transitions. Ensembling these models contributes to tackle the fluctuation of wind power, and training submodels targets on the distinguished properties in heterogeneous timescales of forecasting, from minutes to days. In addition, feature engineering, imputation techniques and the design of offline evaluation are also described in details. The proposed solution achieves an overall online score of -45.213 in Phase 3.
Bi-fidelity Modeling of Uncertain and Partially Unknown Systems using DeepONets
De, Subhayan, Reynolds, Matthew, Hassanaly, Malik, King, Ryan N., Doostan, Alireza
Recent advances in modeling large-scale complex physical systems have shifted research focuses towards data-driven techniques. However, generating datasets by simulating complex systems can require significant computational resources. Similarly, acquiring experimental datasets can prove difficult as well. For these systems, often computationally inexpensive, but in general inaccurate, models, known as the low-fidelity models, are available. In this paper, we propose a bi-fidelity modeling approach for complex physical systems, where we model the discrepancy between the true system's response and low-fidelity response in the presence of a small training dataset from the true system's response using a deep operator network (DeepONet), a neural network architecture suitable for approximating nonlinear operators. We apply the approach to model systems that have parametric uncertainty and are partially unknown. Three numerical examples are used to show the efficacy of the proposed approach to model uncertain and partially unknown complex physical systems.
AI, analytics key to developing African hydrocarbons - IT-Online
Africa has had massive oil and gas discoveries in recent years โ including the Greater Tortue Ahmeyim offshore Senegal and Mauritania, the Luiperd and Brulpadda in South Africa and the Rovuma Basin discoveries offshore Mozambique, among others โ but development has been slow owing largely to restricted investment, Covid-19 impacts and a lack of modern digital solutions. With more than 600-million people living without access to electricity in Africa, the accelerated development of Africa's oil and gas is key for making energy poverty history. Now, with the emergence of AI and analytics across the oil and gas sector, an opportunity has risen for Africa to drive modern and sustainable energy growth for years to come. With oil and gas production decreasing in Africa due to natural declines in legacy projects, increasing the use of AI and analytics across the upstream segment could help simplify drilling activities, revitalise the sector and expand the continent's hydrocarbons reserves for energy reliability, saving project developers, operators and owners time and resources. Furthermore, with African hydrocarbon-producing countries such as Nigeria losing billions in revenue due to theft and vandalism of infrastructure โ a condition that is restraining Africa's oil and gas sector from expanding โ AI and analytics tools can help optimisa industry growth by enhancing infrastructure maintenance and security across the entire oil and gas value chain, thereby helping reduce energy and revenue loss, and in the process stimulating investments across the oil and gas sector. What's more, despite Africa accounting for less than 3% of all carbon emissions, global energy transition related policies are hindering the deployment of investments necessary for boosting the continent's hydrocarbons sector.
HypoSVI: Hypocenter inversion with Stein variational inference and Physics Informed Neural Networks
Smith, Jonathan D., Ross, Zachary E., Azizzadenesheli, Kamyar, Muir, Jack B.
We introduce a scheme for probabilistic hypocenter inversion with Stein variational inference. Our approach uses a differentiable forward model in the form of a physics informed neural network, which we train to solve the Eikonal equation. This allows for rapid approximation of the posterior by iteratively optimizing a collection of particles against a kernelized Stein discrepancy. We show that the method is well-equipped to handle highly multimodal posterior distributions, which are common in hypocentral inverse problems. A suite of experiments is performed to examine the influence of the various hyperparameters. Once trained, the method is valid for any seismic network geometry within the study area without the need to build travel time tables. We show that the computational demands scale efficiently with the number of differential times, making it ideal for large-N sensing technologies like Distributed Acoustic Sensing. The techniques outlined in this manuscript have considerable implications beyond just ray-tracing procedures, with the work flow applicable to other fields with computationally expensive inversion procedures such as full waveform inversion.
A General Framework for the Representation of Function and Affordance: A Cognitive, Causal, and Grounded Approach, and a Step Toward AGI
In AI research, so far, the attention paid to the characterization and representation of function and affordance has been sporadic and sparse, even though this aspect features prominently in an intelligent system's functioning. In the sporadic and sparse, though commendable efforts so far devoted to the characterization and understanding of function and affordance, there has also been no general framework that could unify all the different use domains and situations related to the representation and application of functional concepts. This paper develops just such a general framework, with an approach that emphasizes the fact that the representations involved must be explicitly cognitive and conceptual, and they must also contain causal characterizations of the events and processes involved, as well as employ conceptual constructs that are grounded in the referents to which they refer, in order to achieve maximal generality. The basic general framework is described, along with a set of basic guiding principles with regards to the representation of functionality. To properly and adequately characterize and represent functionality, a descriptive representation language is needed. This language is defined and developed, and many examples of its use are described. The general framework is developed based on an extension of the general language meaning representational framework called conceptual dependency. To support the general characterization and representation of functionality, the basic conceptual dependency framework is enhanced with representational devices called structure anchor and conceptual dependency elaboration, together with the definition of a set of ground level concepts. These novel representational constructs are defined, developed, and described. A general framework dealing with functionality would represent a major step toward achieving Artificial General Intelligence.
On the Elements of Datasets for Cyber Physical Systems Security
Datasets are essential to apply AI algorithms to Cyber Physical System (CPS) Security. Due to scarcity of real CPS datasets, researchers elected to generate their own datasets using either real or virtualized testbeds. However, unlike other AI domains, a CPS is a complex system with many interfaces that determine its behavior. A dataset that comprises merely a collection of sensor measurements and network traffic may not be sufficient to develop resilient AI defensive or offensive agents. In this paper, we study the \emph{elements} of CPS security datasets required to capture the system behavior and interactions, and propose a dataset architecture that has the potential to enhance the performance of AI algorithms in securing cyber physical systems. The framework includes dataset elements, attack representation, and required dataset features. We compare existing datasets to the proposed architecture to identify the current limitations and discuss the future of CPS dataset generation using testbeds.
Perceptive Locomotion through Nonlinear Model Predictive Control
Grandia, Ruben, Jenelten, Fabian, Yang, Shaohui, Farshidian, Farbod, Hutter, Marco
Abstract--Dynamic locomotion in rough terrain requires accurate foot placement, collision avoidance, and planning of the underactuated dynamics of the system. Reliably optimizing for such motions and interactions in the presence of imperfect and often incomplete perceptive information is challenging. We present a complete perception, planning, and control pipeline, that can optimize motions for all degrees of freedom of the robot in real-time. To mitigate the numerical challenges posed by the terrain a sequence of convex inequality constraints is extracted as local approximations of foothold feasibility and embedded into an online model predictive controller. Steppability classification, plane segmentation, and a signed distance field are precomputed per elevation map to minimize the computational effort during the optimization. In the shown configuration, the top foothold is 60 cm above the lowest foothold. These approaches build on a strict hierarchy of first selecting footholds and optimizing torso motion afterward. Still, complex terrains that jointly optimized has shown impressive results in simulation require precise foot placements, e.g., negative obstacles and [18]-[20] and removes the need for engineered torsofoot stepping stones as shown in Figure 1, remain difficult. Complex motions can be automatically A key challenge lies in the fact that both the terrain and discovered by including the entire terrain in the optimization. Additionally, due to the non-convexity, nonlinearity, mature methods exist for perceptive locomotion with a slow, and discontinuity introduced by optimizing over static gait [4]-[8] and for blind, dynamic locomotion that arbitrary terrain, these methods can get stuck in poor local assumes flat terrain [9]-[11]. Dedicated work on providing an initial guess is recently shown the ability to generalize blind locomotion needed to find feasible motions reliably [21]. Still, tightly integrating perception to achieve coordinated and This work presents a planning and control framework precise foot placement remains an active research problem.
Choquet regularization for reinforcement learning
Han, Xia, Wang, Ruodu, Zhou, Xun Yu
We propose \emph{Choquet regularizers} to measure and manage the level of exploration for reinforcement learning (RL), and reformulate the continuous-time entropy-regularized RL problem of Wang et al. (2020, JMLR, 21(198)) in which we replace the differential entropy used for regularization with a Choquet regularizer. We derive the Hamilton--Jacobi--Bellman equation of the problem, and solve it explicitly in the linear--quadratic (LQ) case via maximizing statically a mean--variance constrained Choquet regularizer. Under the LQ setting, we derive explicit optimal distributions for several specific Choquet regularizers, and conversely identify the Choquet regularizers that generate a number of broadly used exploratory samplers such as $\epsilon$-greedy, exponential, uniform and Gaussian.