Energy
What Does a Static, Sustainable Economy Look Like?
I am not an economist. Come to think of it, I am not a lawyer either. But I would like to speculate a bit about what a static, sustainable economy might look like--or, at least, what conditions might have to be satisfied for such an economy to be realistic. On the presumption our present economy is heavily rooted in single-use packaging, replace not repair, and growing populations to drive markets, we might conclude our consumption of non-renewable resources will be decreasingly sustainable. It is already apparent the most "advanced" economies are consuming resources far above their nominal share based on population. For a long time, a growing population assured increased consumption and thus an increasing GDP.
Can AI Save the Planet From Global Warming And Climate Change?
Climate change is one of the biggest problems of the 21st century. Human activities are affecting the environment and are releasing excess CO2 and other greenhouse gasses causing serious problems like temperature rise, global warming, etc. This is saying that Artificial intelligence can help mankind against climate change and global warming. Different countries are taking steps to fight against climate change, but these are not enough because many are not showing their interest. According to the different reports, the glaciers of Antarctica are melting rapidly.
Automated fragment identification for electron ionisation mass spectrometry: application to atmospheric measurements of halocarbons
Guillevic, Myriam, Guillevic, Aurore, Vollmer, Martin, Schlauri, Paul, Hill, Matthias, Emmenegger, Lukas, Reimann, Stefan
Background: Non-target screening consists in searching a sample for all present substances, suspected or unknown, with very little prior knowledge about the sample. This approach has been introduced more than a decade ago in the field of water analysis, but is still very scarce for indoor and atmospheric trace gas measurements, despite the clear need for a better understanding of the atmospheric trace gas composition. For a systematic detection of emerging trace gases in the atmosphere, a new and powerful analytical method is gas chromatography (GC) of preconcentrated samples, followed by electron ionisation, high resolution mass spectrometry (EI-HRMS). In this work, we present data analysis tools to enable automated identification of unknown compounds measured by GC-EI-HRMS. Results: Based on co-eluting mass/charge fragments, we developed an innovative data analysis method to reliably reconstruct the chemical formulae of the fragments, using efficient combinatorics and graph theory. The method (i) does not to require the presence of the molecular ion, which is absent in $\sim$40% of EI spectra, and (ii) permits to use all measured data while giving more weight to mass/charge ratios measured with better precision. Our method has been trained and validated on >50 halocarbons and hydrocarbons with a molar masses of 30-330 g mol-1 , measured with a mass resolution of approx. 3500. For >90% of the compounds, more than 90% of the reconstructed signal is correct. Cases of wrong identification can be attributed to the scarcity of detected fragments per compound (less than six measured mass/charge) or the lack of isotopic constrain (no rare isotopocule detected). Conclusions: Our method enables to reconstruct most probable chemical formulae independently from spectral databases. Therefore, it demonstrates the suitability of EI-HRMS data for non-target analysis and paves the way for the identification of substances for which no EI mass spectrum is registered in databases. We illustrate the performances of our method for atmospheric trace gases and suggest that it may be well suited for many other types of samples.
Dual Online Stein Variational Inference for Control and Dynamics
Barcelos, Lucas, Lambert, Alexander, Oliveira, Rafael, Borges, Paulo, Boots, Byron, Ramos, Fabio
Model predictive control (MPC) schemes have a proven track record for delivering aggressive and robust performance in many challenging control tasks, coping with nonlinear system dynamics, constraints, and observational noise. Despite their success, these methods often rely on simple control distributions, which can limit their performance in highly uncertain and complex environments. MPC frameworks must be able to accommodate changing distributions over system parameters, based on the most recent measurements. In this paper, we devise an implicit variational inference algorithm able to estimate distributions over model parameters and control inputs on-the-fly. The method incorporates Stein Variational gradient descent to approximate the target distributions as a collection of particles, and performs updates based on a Bayesian formulation. This enables the approximation of complex multi-modal posterior distributions, typically occurring in challenging and realistic robot navigation tasks. We demonstrate our approach on both simulated and real-world experiments requiring real-time execution in the face of dynamically changing environments.
Markov Modeling of Time-Series Data using Symbolic Analysis
Markov models are often used to capture the temporal patterns of sequential data for statistical learning applications. While the Hidden Markov modeling-based learning mechanisms are well studied in literature, we analyze a symbolic-dynamics inspired approach. Under this umbrella, Markov modeling of time-series data consists of two major steps -- discretization of continuous attributes followed by estimating the size of temporal memory of the discretized sequence. These two steps are critical for the accurate and concise representation of time-series data in the discrete space. Discretization governs the information content of the resultant discretized sequence. On the other hand, memory estimation of the symbolic sequence helps to extract the predictive patterns in the discretized data. Clearly, the effectiveness of signal representation as a discrete Markov process depends on both these steps. In this paper, we will review the different techniques for discretization and memory estimation for discrete stochastic processes. In particular, we will focus on the individual problems of discretization and order estimation for discrete stochastic process. We will present some results from literature on partitioning from dynamical systems theory and order estimation using concepts of information theory and statistical learning. The paper also presents some related problem formulations which will be useful for machine learning and statistical learning application using the symbolic framework of data analysis. We present some results of statistical analysis of a complex thermoacoustic instability phenomenon during lean-premixed combustion in jet-turbine engines using the proposed Markov modeling method.
Improved Analysis of Robustness of the Tsallis-INF Algorithm to Adversarial Corruptions in Stochastic Multiarmed Bandits
Masoudian, Saeed, Seldin, Yevgeny
We derive improved regret bounds for the Tsallis-INF algorithm of Zimmert and Seldin (2021). In the adversarial regime with a self-bounding constraint and the stochastic regime with adversarial corruptions as its special case we improve the dependence on corruption magnitude $C$. In particular, for $C = \Theta\left(\frac{T}{\log T}\right)$, where $T$ is the time horizon, we achieve an improvement by a multiplicative factor of $\sqrt{\frac{\log T}{\log\log T}}$ relative to the bound of Zimmert and Seldin (2021). We also improve the dependence of the regret bound on time horizon from $\log T$ to $\log \frac{(K-1)T}{(\sum_{i\neq i^*}\frac{1}{\Delta_i})^2}$, where $K$ is the number of arms, $\Delta_i$ are suboptimality gaps for suboptimal arms $i$, and $i^*$ is the optimal arm. Additionally, we provide a general analysis, which allows to achieve the same kind of improvement for generalizations of Tsallis-INF to other settings beyond multiarmed bandits.
Learning to Optimize: A Primer and A Benchmark
Chen, Tianlong, Chen, Xiaohan, Chen, Wuyang, Heaton, Howard, Liu, Jialin, Wang, Zhangyang, Yin, Wotao
Learning to optimize (L2O) is an emerging approach that leverages machine learning to develop optimization methods, aiming at reducing the laborious iterations of hand engineering. It automates the design of an optimization method based on its performance on a set of training problems. This data-driven procedure generates methods that can efficiently solve problems similar to those in the training. In sharp contrast, the typical and traditional designs of optimization methods are theory-driven, so they obtain performance guarantees over the classes of problems specified by the theory. The difference makes L2O suitable for repeatedly solving a certain type of optimization problems over a specific distribution of data, while it typically fails on out-of-distribution problems. The practicality of L2O depends on the type of target optimization, the chosen architecture of the method to learn, and the training procedure. This new paradigm has motivated a community of researchers to explore L2O and report their findings. This article is poised to be the first comprehensive survey and benchmark of L2O for continuous optimization. We set up taxonomies, categorize existing works and research directions, present insights, and identify open challenges.
Forum: Limits to using data and AI to boost food security
I refer to the Opinion piece "How AI can strengthen food resilience" (March 17). While I appreciate that artificial intelligence (AI) can help to strengthen Singapore's food resilience, I am disappointed that the authors did not also provide its limitations, and more importantly, other critical factors that can severely impact Singapore's food resilience. Take Singapore's vertical farms for vegetables and fish as an illustration. These vertical farms are energy intensive. Indoor plants need artificial lighting and environment control; indoor fish farms, otherwise known as recirculating aquaculture systems, need recirculating pumps, filtration systems, oxygenation systems, and so on, all of which are energy intensive.
AI Technologies To Harness Oceanography's Potential For Sustainability
One thing that dominates the surface of the earth is the ocean. From regulating our climate, securing transportation of goods across nations, from minerals to polymetallic nodules, harnessing clean energy sources to deep research, it holds numerous potentials that are yet to be harnessed. The United Nations has declared 2021 to 2030 – a Decade of Ocean Science for Sustainable Development to support efforts to reverse the trend of declining ocean health and bring ocean stakeholders worldwide together behind a collective structure to work for ocean sustainability. In a recent research by the University of Bath, two AI algorithms -- Latent Variable Gaussian Process (LVGP) model and Probabilistic Principal Component Analysis (PPCA) were used to understand the sonar echoes in the ocean. The research aimed at observing the changes that can happen with sonar echoes at different depths, salinity, and temperature.
Cooperative Learning of Zero-Shot Machine Reading Comprehension
Luo, Hongyin, Li, Shang-Wen, Yu, Seunghak, Glass, James
Pretrained language models have significantly improved the performance of down-stream language understanding tasks, including extractive question answering, by providing high-quality contextualized word embeddings. However, learning question answering models still need large-scaled data annotation in specific domains. In this work, we propose a cooperative, self-play learning framework, REGEX, for question generation and answering. REGEX is built upon a masked answer extraction task with an interactive learning environment containing an answer entity REcognizer, a question Generator, and an answer EXtractor. Given a passage with a masked entity, the generator generates a question around the entity, and the extractor is trained to extract the masked entity with the generated question and raw texts. The framework allows the training of question generation and answering models on any text corpora without annotation. We further leverage a reinforcement learning technique to reward generating high-quality questions and to improve the answer extraction model's performance. Experiment results show that REGEX outperforms the state-of-the-art (SOTA) pretrained language models and zero-shot approaches on standard question-answering benchmarks, and yields the new SOTA performance under the zero-shot setting.