Energy
Hybridization of Capsule and LSTM Networks for unsupervised anomaly detection on multivariate data
Elhalwagy, Ayman, Kalganova, Tatiana
Deep learning techniques have recently shown promise in the field of anomaly detection, providing a flexible and effective method of modelling systems in comparison to traditional statistical modelling and signal processing-based methods. However, there are a few well publicised issues Neural Networks (NN)s face such as generalisation ability, requiring large volumes of labelled data to be able to train effectively and understanding spatial context in data. This paper introduces a novel NN architecture which hybridises the Long-Short-Term-Memory (LSTM) and Capsule Networks into a single network in a branched input Autoencoder architecture for use on multivariate time series data. The proposed method uses an unsupervised learning technique to overcome the issues with finding large volumes of labelled training data. Experimental results show that without hyperparameter optimisation, using Capsules significantly reduces overfitting and improves the training efficiency. Additionally, results also show that the branched input models can learn multivariate data more consistently with or without Capsules in comparison to the non-branched input models. The proposed model architecture was also tested on an open-source benchmark, where it achieved state-of-the-art performance in outlier detection, and overall performs best over the metrics tested in comparison to current state-of-the art methods.
Adversarial Attacks and Defense Methods for Power Quality Recognition
Tian, Jiwei, Wang, Buhong, Li, Jing, Wang, Zhen, Ozay, Mete
Vulnerability of various machine learning methods to adversarial examples has been recently explored in the literature. Power systems which use these vulnerable methods face a huge threat against adversarial examples. To this end, we first propose a signal-specific method and a universal signal-agnostic method to attack power systems using generated adversarial examples. Black-box attacks based on transferable characteristics and the above two methods are also proposed and evaluated. We then adopt adversarial training to defend systems against adversarial attacks. Experimental analyses demonstrate that our signal-specific attack method provides less perturbation compared to the FGSM (Fast Gradient Sign Method), and our signal-agnostic attack method can generate perturbations fooling most natural signals with high probability. What's more, the attack method based on the universal signal-agnostic algorithm has a higher transfer rate of black-box attacks than the attack method based on the signal-specific algorithm. In addition, the results show that the proposed adversarial training improves robustness of power systems to adversarial examples. OWER quality refers to a variety of electromagnetic phenomena that characterize voltage and current measured at a given time instance and location in a power system [2]. Disturbance of power quality (PQ) signals can cause severe problems in electrical grids [3].
Bounded nonlinear forecasts of partially observed geophysical systems with physics-constrained deep learning
Ouala, Said, Brunton, Steven L., Pascual, Ananda, Chapron, Bertrand, Collard, Fabrice, Gaultier, Lucile, Fablet, Ronan
The complexity of real-world geophysical systems is often compounded by the fact that the observed measurements depend on hidden variables. These latent variables include unresolved small scales and/or rapidly evolving processes, partially observed couplings, or forcings in coupled systems. This is the case in ocean-atmosphere dynamics, for which unknown interior dynamics can affect surface observations. The identification of computationally-relevant representations of such partially-observed and highly nonlinear systems is thus challenging and often limited to short-term forecast applications. Here, we investigate the physics-constrained learning of implicit dynamical embeddings, leveraging neural ordinary differential equation (NODE) representations. A key objective is to constrain their boundedness, which promotes the generalization of the learned dynamics to arbitrary initial condition. The proposed architecture is implemented within a deep learning framework, and its relevance is demonstrated with respect to state-of-the-art schemes for different case-studies representative of geophysical dynamics.
Learning curve effect on the global variable renewable energy deployment
The traditional electricity market in the world was dominated by fossil fuel technologies. Today renewable energy technologies, particularly VRE, are cheaper than fossil fuels in most countries of the world. The large-scale deployment of solar and wind generation in the past decade has led to a paradigm shift in the power system and electricity markets. How the deployment of VRE and other renewable energy technologies changes the dynamics of merit order and the marginal cost of electricity generation is present in this story. In this article, I discussed the trend of renewable energy and VRE from a global perspective.
AES to use AI-enabled bidding software for solar and energy storage projects
Fluence announced an agreement with The AES Corporation, a Fortune 500 global energy company, to implement the AI-powered Fluence IQ Bidding Application to maximize the value of a 1.1GW portfolio of solar and energy storage projects in the Western US. In October of last year, Fluence acquired AMS' software and digital intelligence platform for renewables and energy storage. The platform is designed to improve revenue of energy storage assets in wholesale markets. AMS' technology uses artificial intelligence, advanced price forecasting, portfolio optimization and market bidding to ensure energy storage and flexible generation assets are responding optimally to price signals sent by the market. The way the Fluence IQ Bidding Application works is it recommends bids into daily and hourly auctions for energy and grid services, anticipating opportunities using advanced forecasting to take advantage of favorable pricing, while minimizing exposure to unfavorable pricing.
The next generation of energy and environment startups using data and AI to save the planet - Dataconomy
Energy and the environment were significant threads covered at Web Summit and garner additional importance when considering the travel and accommodation footprint created by almost 44,000 attendees. It calls for greater awareness of the CO2 produced by the event and its participants. While Web Summit took place on the same days as COP26, it still managed to attract energy and environmental industry pioneers. Being selected at the Web Summit Alpha program means something. It means your startups are disrupting their industries.
Learning in Restless Bandits under Exogenous Global Markov Process
Gafni, Tomer, Yemini, Michal, Cohen, Kobi
We consider an extension to the restless multi-armed bandit (RMAB) problem with unknown arm dynamics, where an unknown exogenous global Markov process governs the rewards distribution of each arm. Under each global state, the rewards process of each arm evolves according to an unknown Markovian rule, which is non-identical among different arms. At each time, a player chooses an arm out of $N$ arms to play, and receives a random reward from a finite set of reward states. The arms are restless, that is, their local state evolves regardless of the player's actions. Motivated by recent studies on related RMAB settings, the regret is defined as the reward loss with respect to a player that knows the dynamics of the problem, and plays at each time $t$ the arm that maximizes the expected immediate value. The objective is to develop an arm-selection policy that minimizes the regret. To that end, we develop the Learning under Exogenous Markov Process (LEMP) algorithm. We analyze LEMP theoretically and establish a finite-sample bound on the regret. We show that LEMP achieves a logarithmic regret order with time. We further analyze LEMP numerically and present simulation results that support the theoretical findings and demonstrate that LEMP significantly outperforms alternative algorithms.
Migrating Techniques from Search-based Multi-Agent Path Finding Solvers to SAT-based Approach
Surynek, Pavel, Stern, Roni, Boyarski, Eli, Felner, Ariel
In the multi-agent path finding problem (MAPF) we are given a set of agents each with respective start and goal positions. The task is to find paths for all agents while avoiding collisions, aiming to minimize a given objective function. Many MAPF solvers were introduced in the past decade for optimizing two specific objective functions: sum-of-costs and makespan. Two prominent categories of solvers can be distinguished: search-based solvers and compilation-based solvers. Search-based solvers were developed and tested for the sum-of-costs objective, while the most prominent compilation-based solvers that are built around Boolean satisfiability (SAT) were designed for the makespan objective. Very little is known on the performance and relevance of solvers from the compilation-based approach on the sum-of-costs objective. In this paper, we start to close the gap between these cost functions in the compilation-based approach. Our main contribution is a new SAT-based MAPF solver called MDD-SAT, that is directly aimed to optimally solve the MAPF problem under the sum-of-costs objective function. Using both a lower bound on the sum-of-costs and an upper bound on the makespan, MDD-SAT is able to generate a reasonable number of Boolean variables in our SAT encoding. We then further improve the encoding by borrowing ideas from ICTS, a search-based solver. In addition, we show that concepts applicable in search-based solvers like ICTS and ICBS are applicable in the SAT-based approach as well. Specifically, we integrate independence detection, a generic technique for decomposing an MAPF instance into independent subproblems, into our SAT-based approach, and we design a relaxation of our optimal SAT-based solver that results in a bounded suboptimal SAT-based solver. Experimental evaluation on several domains shows that there are many scenarios where our SAT-based methods outperform state-of-the-art sum-of-costs search-based solvers, such as variants of the ICTS and ICBS algorithms.
Improving performance of aircraft detection in satellite imagery while limiting the labelling effort: Hybrid active learning
Imbert, Julie, Dashyan, Gohar, Goupilleau, Alex, Ceillier, Tugdual, Corbineau, Marie-Caroline
The earth observation industry provides satellite imagery with high spatial resolution and short revisit time. To allow efficient operational employment of these images, automating certain tasks has become necessary. In the defense domain, aircraft detection on satellite imagery is a valuable tool for analysts. Obtaining high performance detectors on such a task can only be achieved by leveraging deep learning and thus us-ing a large amount of labeled data. To obtain labels of a high enough quality, the knowledge of military experts is needed.We propose a hybrid clustering active learning method to select the most relevant data to label, thus limiting the amount of data required and further improving the performances. It combines diversity- and uncertainty-based active learning selection methods. For aircraft detection by segmentation, we show that this method can provide better or competitive results compared to other active learning methods.
Case-based reasoning for rare events prediction on strategic sites
Vidal, Vincent, Corbineau, Marie-Caroline, Ceillier, Tugdual
Satellite imagery is now widely used in the defense sector for monitoring locations of interest. Although the increasing amount of data enables pattern identification and therefore prediction, carrying this task manually is hardly feasible. We hereby propose a cased-based reasoning approach for automatic prediction of rare events on strategic sites. This method allows direct incorporation of expert knowledge, and is adapted to irregular time series and small-size datasets. Experiments are carried out on two use-cases using real satellite images: the prediction of submarines arrivals and departures from a naval base, and the forecasting of imminent rocket launches on two space bases. The proposed method significantly outperforms a random selection of reference cases on these challenging applications, showing its strong potential. Keywords: Predictive analysis · Case-based reasoning · Earth observation · Submarine activity · Space launch.