Energy
Analysis of autocorrelation times in Neural Markov Chain Monte Carlo simulations
Białas, Piotr, Korcyl, Piotr, Stebel, Tomasz
In case of complicated probability distributions most formulations resort to the construction of an associated Markov chain of consecutive proposals. The statistical uncertainty of any outcome of Monte Carlo simulation depends directly on the number of statistically independent configurations used to estimate it. Hence, the effectiveness of simulation algorithms is measured by autocorrelation time which quantify how many configurations are produced by the algorithm before a new, statistically independent configuration appears. Increasing autocorrelation times, a phenomenon called critical slowing down, is usually the main factor which limits the statistical precision of outputs. In the context of field theory simulations in elementary particle physics several proposals were advanced in order to alleviate that problem, in particular metadynamics [3, 4], instanton updates [5] or multiscale thermalization [6]. The recent great interest in machine learning techniques has also provided new ideas in the domain of Monte Carlo simulations which aim at reducing the autocorrelation times. The ability of artificial neural networks to approximate a very wide class of probability distributions was used in Ref.[7] to propose a variational estimate of free energy of statistical systems. Subsequently the idea was extended and used as a mechanism of providing uncorrelated proposals in a Monte Carlo simulation in Ref.[8].
DDG-DA: Data Distribution Generation for Predictable Concept Drift Adaptation
Li, Wendi, Yang, Xiao, Liu, Weiqing, Xia, Yingce, Bian, Jiang
In many real-world scenarios, we often deal with streaming data that is sequentially collected over time. Due to the non-stationary nature of the environment, the streaming data distribution may change in unpredictable ways, which is known as concept drift. To handle concept drift, previous methods first detect when/where the concept drift happens and then adapt models to fit the distribution of the latest data. However, there are still many cases that some underlying factors of environment evolution are predictable, making it possible to model the future concept drift trend of the streaming data, while such cases are not fully explored in previous work. In this paper, we propose a novel method DDG-DA, that can effectively forecast the evolution of data distribution and improve the performance of models. Specifically, we first train a predictor to estimate the future data distribution, then leverage it to generate training samples, and finally train models on the generated data. We conduct experiments on three real-world tasks (forecasting on stock price trend, electricity load and solar irradiance) and obtain significant improvement on multiple widely-used models.
'Mystery hut' on the Moon is a rabbit-shaped rock, scientists reveal
An object found on the surface of the moon that was dubbed a'mystery hut' is actually a rabbit-shaped rock, scientists have revealed. China's Yutu 2 rover spotted the object on the far side of the moon in December, thanks to its panoramic and infrared on-board cameras, and approached it for closer inspection. Now, the Yutu 2 team have confirmed that it is an oddly-shaped rock that they claim looks like a small but'lifelike' crouching bunny like a statue set in stone, surrounded by its own rocky'droppings' and morsels of food. The finding is a coincidence as the name of the rover, Yutu, happens to be Chinese for'Jade Rabbit'. China's Yutu 2 team say the an oddly-shaped rock looks like a small but'lifelike' crouching bunny like a statue set in stone, surrounded by its own rocky'droppings' and morsels of food Yutu-2 is the robotic lunar rover component of China's Chang'e 4 mission to the far side of the Moon.
Over €5 million funding for University of Warwick projects tackling sustainability and fundamental question of our universe
Three new research projects at the University of Warwick that will investigate new avenues for a sustainable future as well as a fundamental question of our universe's past have been awarded a total of more than €5 million in European Research Council Starting Grants. Following the first call for proposals under the EU's new R&I programme, Horizon Europe, €619 million will be invested in excellent projects dreamed up by 397 scientists and scholars. Grants worth on average €1.5 million will help ambitious younger researchers launch their own projects, form their teams and pursue their best ideas. The selected proposals cover all disciplines of research, from the medical applications of artificial intelligence, to the science of controlling matter by using light, to designing a legal regime for fair influencer marketing. The SHINE project (Shining Light on Metal Halide Perovskite Stability with Nanoscale Optical Microscopy and Ultrafast Spectroscopy), led by Dr Rebecca Milot of the University of Warwick's Department of Physics, has received €2,473,363 and will investigate one of the most promising new materials for solar energy conversion, metal halide perovskites.
Descriptive vs. inferential community detection: pitfalls, myths and half-truths
Community detection is one of the most important methodological fields of network science, and one which has attracted a significant amount of attention over the past decades. This area deals with the automated division of a network into fundamental building blocks, with the objective of providing a summary of its large-scale structure. Despite its importance and widespread adoption, there is a noticeable gap between what is considered the state-of-the-art and the methods that are actually used in practice in a variety of fields. Here we attempt to address this discrepancy by dividing existing methods according to whether they have a "descriptive" or an "inferential" goal. While descriptive methods find patterns in networks based on intuitive notions of community structure, inferential methods articulate a precise generative model, and attempt to fit it to data. In this way, they are able to provide insights into the mechanisms of network formation, and separate structure from randomness in a manner supported by statistical evidence. We review how employing descriptive methods with inferential aims is riddled with pitfalls and misleading answers, and thus should be in general avoided. We argue that inferential methods are more typically aligned with clearer scientific questions, yield more robust results, and should be in many cases preferred. We attempt to dispel some myths and half-truths often believed when community detection is employed in practice, in an effort to improve both the use of such methods as well as the interpretation of their results.
Multiaxis nose-pointing-and-shooting in a biomimetic morphing-wing aircraft
Supermaneuverability, in broad terms, refers to the complex forms of non-conventional maneuverability that are found in high-performance combat aircraft. This capability includes maneuvers such as the Pugachev cobra, Kulbit and Herbst maneuver [1-3]; as well as broader, competing, classifications of flight behavior, including rapid nose-pointing-and-shooting (RaNPAS), pure sideslip maneuvering (PSM) [4,5] and direct force Page 3 of 32 maneuvering (DFM) [6]. The development of supermaneuverable aircraft has been founded on advances in the study of unstable airframes, and the development of vectored propulsion technology [1,2]. Modern supermaneuverable aircraft remain characterized by these mechanisms; but increasing interdisciplinary contact with biological studies of maneuverability in flying creatures has led to parallel studies of an alternative, biomimetic, mechanism of supermaneuverability: one based on controlled wing morphing and motion. Thus far, biomimetic perching in unmanned aerial vehicles (UAVs) has been a central focus of these studies [7-9], with extensions into hover-to-cruise transition maneuvers [10], and incidence-based stall turns [11]. These maneuvers are primarily bio-inspired, and as such, studies of the biomimetic mechanism supermaneuverability have remained disjointed from studies of the thrust-vectored mechanism: the relationships between biomimetic and thrustvectored maneuvers, mechanisms, and capabilities are rarely recognized [3].
Wind Park Power Prediction: Attention-Based Graph Networks and Deep Learning to Capture Wake Losses
Bentsen, Lars Ødegaard, Warakagoda, Narada Dilp, Stenbro, Roy, Engelstad, Paal
With the increased penetration of wind energy into the power grid, it has become increasingly important to be able to predict the expected power production for larger wind farms. Deep learning (DL) models can learn complex patterns in the data and have found wide success in predicting wake losses and expected power production. This paper proposes a modular framework for attention-based graph neural networks (GNN), where attention can be applied to any desired component of a graph block. The results show that the model significantly outperforms a multilayer perceptron (MLP) and a bidirectional LSTM (BLSTM) model, while delivering performance on-par with a vanilla GNN model. Moreover, we argue that the proposed graph attention architecture can easily adapt to different applications by offering flexibility into the desired attention operations to be used, which might depend on the specific application. Through analysis of the attention weights, it was showed that employing attention-based GNNs can provide insights into what the models learn. In particular, the attention networks seemed to realise turbine dependencies that aligned with some physical intuition about wake losses.
Time Series Forecasting Using Fuzzy Cognitive Maps: A Survey
Orang, Omid, Silva, Petrônio Cândido de Lima e, Guimarães, Frederico Gadelha
Increasing complexity comes from some factors including uncertainty, ambiguity, inconsistency, multiple dimensionalities, increasing the number of effective factors and relation between them. Some of these features are common among most real-world problems which are considered complex and dynamic problems. In other words, since the data and relations in real world applications are usually highly complex and inaccurate, modeling real complex systems based on observed data is a challenging task especially for large scale, inaccurate and non stationary datasets. Therefore, to cover and address these difficulties, the existence of a computational system with the capability of extracting knowledge from the complex system with the ability to simulate its behavior is essential. In other words, it is needed to find a robust approach and solution to handle real complex problems in an easy and meaningful way [1]. Hard computing methods depend on quantitative values with expensive solutions and lack of ability to represent the problem in real life due to some uncertainties. In contrast, soft computing approaches act as alternative tools to deal with the reasoning of complex problems [2]. Using soft computing methods such as fuzzy logic, neural network, genetic algorithms or a combination of these allows achieving robustness, tractable and more practical solutions. Generally, two types of methods are used for analyzing and modeling dynamic systems including quantitative and qualitative approaches.
Aerial Images Meet Crowdsourced Trajectories: A New Approach to Robust Road Extraction
Liu, Lingbo, Yang, Zewei, Li, Guanbin, Wang, Kuo, Chen, Tianshui, Lin, Liang
Land remote sensing analysis is a crucial research in earth science. In this work, we focus on a challenging task of land analysis, i.e., automatic extraction of traffic roads from remote sensing data, which has widespread applications in urban development and expansion estimation. Nevertheless, conventional methods either only utilized the limited information of aerial images, or simply fused multimodal information (e.g., vehicle trajectories), thus cannot well recognize unconstrained roads. To facilitate this problem, we introduce a novel neural network framework termed Cross-Modal Message Propagation Network (CMMPNet), which fully benefits the complementary different modal data (i.e., aerial images and crowdsourced trajectories). Specifically, CMMPNet is composed of two deep Auto-Encoders for modality-specific representation learning and a tailor-designed Dual Enhancement Module for cross-modal representation refinement. In particular, the complementary information of each modality is comprehensively extracted and dynamically propagated to enhance the representation of another modality. Extensive experiments on three real-world benchmarks demonstrate the effectiveness of our CMMPNet for robust road extraction benefiting from blending different modal data, either using image and trajectory data or image and Lidar data. From the experimental results, we observe that the proposed approach outperforms current state-of-the-art methods by large margins.Our source code is resealed on the project page \url{http://lingboliu.com/multimodal road extraction.html}
Sustainable AI: Environmental Implications, Challenges and Opportunities
Wu, Carole-Jean, Raghavendra, Ramya, Gupta, Udit, Acun, Bilge, Ardalani, Newsha, Maeng, Kiwan, Chang, Gloria, Behram, Fiona Aga, Huang, James, Bai, Charles, Gschwind, Michael, Gupta, Anurag, Ott, Myle, Melnikov, Anastasia, Candido, Salvatore, Brooks, David, Chauhan, Geeta, Lee, Benjamin, Lee, Hsien-Hsin S., Akyildiz, Bugra, Balandat, Maximilian, Spisak, Joe, Jain, Ravi, Rabbat, Mike, Hazelwood, Kim
This paper explores the environmental impact of the super-linear growth trends for AI from a holistic perspective, spanning Data, Algorithms, and System Hardware. We characterize the carbon footprint of AI computing by examining the model development cycle across industry-scale machine learning use cases and, at the same time, considering the life cycle of system hardware. Taking a step further, we capture the operational and manufacturing carbon footprint of AI computing and present an end-to-end analysis for what and how hardware-software design and at-scale optimization can help reduce the overall carbon footprint of AI. Based on the industry experience and lessons learned, we share the key challenges and chart out important development directions across the many dimensions of AI. We hope the key messages and insights presented in this paper can inspire the community to advance the field of AI in an environmentally-responsible manner.