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Site-specific graph neural network for predicting protonation energy of oxygenate molecules

arXiv.org Machine Learning

Bio-oil molecule assessment is essential for the sustainable development of chemicals and transportation fuels. These oxygenated molecules have adequate carbon, hydrogen, and oxygen atoms that can be used for developing new value-added molecules (chemicals or transportation fuels). One motivation for our study stems from the fact that a liquid phase upgrading using mineral acid is a cost-effective chemical transformation. In this chemical upgrading process, adding a proton (positively charged atomic hydrogen) to an oxygen atom is a central step. The protonation energies of oxygen atoms in a molecule determine the thermodynamic feasibility of the reaction and likely chemical reaction pathway. A quantum chemical model based on coupled cluster theory is used to compute accurate thermochemical properties such as the protonation energies of oxygen atoms and the feasibility of protonation-based chemical transformations. However, this method is too computationally expensive to explore a large space of chemical transformations. We develop a graph neural network approach for predicting protonation energies of oxygen atoms of hundreds of bioxygenate molecules to predict the feasibility of aqueous acidic reactions. Our approach relies on an iterative local nonlinear embedding that gradually leads to global influence of distant atoms and a output layer that predicts the protonation energy. Our approach is geared to site-specific predictions for individual oxygen atoms of a molecule in comparison with commonly used graph convolutional networks that focus on a singular molecular property prediction. We demonstrate that our approach is effective in learning the location and magnitudes of protonation energies of oxygenated molecules.


Bias In, Bias Out? Evaluating the Folk Wisdom

arXiv.org Machine Learning

We evaluate the folk wisdom that algorithms trained on data produced by biased human decision-makers necessarily reflect this bias. We consider a setting where training labels are only generated if a biased decision-maker takes a particular action, and so bias arises due to selection into the training data. In our baseline model, the more biased the decision-maker is toward a group, the more the algorithm favors that group. We refer to this phenomenon as "algorithmic affirmative action." We then clarify the conditions that give rise to algorithmic affirmative action. Whether a prediction algorithm reverses or inherits bias depends critically on how the decision-maker affects the training data as well as the label used in training. We illustrate our main theoretical results in a simulation study applied to the New York City Stop, Question and Frisk dataset.


Using recurrent neural networks for nonlinear component computation in advection-dominated reduced-order models

arXiv.org Machine Learning

Rapid simulations of advection-dominated problems are vital for multiple engineering and geophysical applications. In this paper, we present a long short-term memory neural network to approximate the nonlinear component of the reduced-order model (ROM) of an advection-dominated partial differential equation. This is motivated by the fact that the nonlinear term is the most expensive component of a successful ROM. For our approach, we utilize a Galerkin projection to isolate the linear and the transient components of the dynamical system and then use discrete empirical interpolation to generate training data for supervised learning. We note that the numerical time-advancement and linear-term computation of the system ensures a greater preservation of physics than does a process that is fully modeled. Our results show that the proposed framework recovers transient dynamics accurately without nonlinear term computations in full-order space and represents a cost-effective alternative to solely equation-based ROMs.


Uncovering Sociological Effect Heterogeneity using Machine Learning

arXiv.org Machine Learning

Individuals do not respond uniformly to treatments, events, or interventions. Sociologists routinely partition samples into subgroups to explore how the effects of treatments vary by covariates like race, gender, and socioeconomic status. In so doing, analysts determine the key subpopulations based on theoretical priors. Data-driven discoveries are also routine, yet the analyses by which sociologists typically go about them are problematic and seldom move us beyond our expectations, and biases, to explore new meaningful subgroups. Emerging machine learning methods allow researchers to explore sources of variation that they may not have previously considered, or envisaged. In this paper, we use causal trees to recursively partition the sample and uncover sources of treatment effect heterogeneity. We use honest estimation, splitting the sample into a training sample to grow the tree and an estimation sample to estimate leaf-specific effects. Assessing a central topic in the social inequality literature, college effects on wages, we compare what we learn from conventional approaches for exploring variation in effects to causal trees. Given our use of observational data, we use leaf-specific matching and sensitivity analyses to address confounding and offer interpretations of effects based on observed and unobserved heterogeneity. We encourage researchers to follow similar practices in their work on variation in sociological effects.


Fine-Tuning Language Models from Human Preferences

arXiv.org Machine Learning

Reward learning enables the application of reinforcement learning (RL) to tasks where reward is defined by human judgment, building a model of reward by asking humans questions. Most work on reward learning has used simulated environments, but complex information about values is often expressed in natural language, and we believe reward learning for language is a key to making RL practical and safe for real-world tasks. In this paper, we build on advances in generative pretraining of language models to apply reward learning to four natural language tasks: continuing text with positive sentiment or physically descriptive language, and summarization tasks on the TL;DR and CNN/Daily Mail datasets. For stylistic continuation we achieve good results with only 5,000 comparisons evaluated by humans. For summarization, models trained with 60,000 comparisons copy whole sentences from the input but skip irrelevant preamble; this leads to reasonable ROUGE scores and very good performance according to our human labelers, but may be exploiting the fact that labelers rely on simple heuristics.


Causal Modeling for Fairness in Dynamical Systems

arXiv.org Artificial Intelligence

In this work, we present causal directed acyclic graphs (DAGs) as a unifying framework for the recent literature on fairness in dynamical systems. We advocate for the use of causal DAGs as a tool in both designing equitable policies and estimating their impacts. By visualizing models of dynamic unfairness graphically, we expose implicit causal assumptions which can then be more easily interpreted and scrutinized by domain experts. We demonstrate that this method of reinterpretation can be used to critique the robustness of an existing model/policy, or uncover new policy evaluation questions. Causal models also enable a rich set of options for evaluating a new candidate policy without incurring the risk of implementing the policy in the real world. We close the paper with causal analyses of several models from the recent literature, and provide an in-depth case study to demonstrate the utility of causal DAGs for modeling fairness in dynamical systems.


Segregation Dynamics with Reinforcement Learning and Agent Based Modeling

arXiv.org Artificial Intelligence

Societies are complex. Properties of social systems can be explained by the interplay and weaving of individual actions. Incentives are key to understand people's choices and decisions. For instance, individual preferences of where to live may lead to the emergence of social segregation. In this paper, we combine Reinforcement Learning (RL) with Agent Based Models (ABM) in order to address the self-organizing dynamics of social segregation and explore the space of possibilities that emerge from considering different types of incentives. Our model promotes the creation of interdependencies and interactions among multiple agents of two different kinds that want to segregate from each other. For this purpose, agents use Deep Q-Networks to make decisions based on the rules of the Schelling Segregation model and the Predator-Prey model. Despite the segregation incentive, our experiments show that spatial integration can be achieved by establishing interdependencies among agents of different kinds. They also reveal that segregated areas are more probable to host older people than diverse areas, which attract younger ones. Through this work, we show that the combination of RL and ABMs can create an artificial environment for policy makers to observe potential and existing behaviors associated to incentives.


Trump loyalist Sen. Lindsey Graham calls attack on Saudi oil installations an 'act of war'

The Japan Times

WASHINGTON โ€“ Several U.S. lawmakers urged caution Tuesday in countering recent attacks on Saudi oil installations, but Trump loyalist Sen. Lindsey Graham branded the incident an "act of war" that merits a decisive response. Graham said it was "clear" that such a sophisticated attack -- drones firing missiles into the world's largest processing plant and an oilfield in Saudi Arabia -- could only have originated with direction and involvement from the "evil regime in Iran." "This is literally an act of war and the goal should be to restore deterrence against Iranian aggression which has clearly been lost," Graham said in a statement. The Republican lawmaker and trusted Trump ally tweeted that Washington should consider an attack on Iran's oil refineries in response, a move that he said "will break the regime's back." Graham has been a defense hawk for years, and he noted that Trump's "measured response" to Iran shooting down an American drone in June "was clearly seen by the Iranian regime as a sign of weakness." A classified briefing book on the attacks was made available to U.S. senators in a secure location in the U.S. Capitol. Other Republican senators, including Marco Rubio and Ron Johnson, said they fully believe Iran was responsible for the Saudi strike.


Microsoft president pens book on impact of AI, rising cyberattacks and more - ET CIO

#artificialintelligence

What is the impact of Artificial Intelligence (AI) on our lives? How can we combat increasing cyberattacks? Is the threat to digital privacy real? Co-written by Carlon Ann Browne, director of communications at Microsoft, the book released on September 10. The book claims not to be a self-glorifying "Microsoft memoir", but a "candid and eye-opening investigation into the most divisive issues facing tech companies and governments today -- cyberwar, privacy, mass surveillance, undermining of democracy, AI, diversity".


Why we need to rethink education in the artificial intelligence age

#artificialintelligence

Artificial intelligence (AI) and emerging technologies (ET) are poised to transform modern society in profound ways. As with electricity in the last century, AI is an enabling technology that will animate everyday products and communications, endowing everything from cars to cameras with the ability to interact with the world around them, and with each other. These developments are just the beginning, and as AI/ET matures, it will have sweeping impacts on our work, security, politics, and very lives.1 These technologies are already impacting the world around us, as Darrell West and I wrote in our April 2018 piece "How artificial intelligence is transforming the world," and I highly recommend that anyone just discovering the topic of AI policy read it thoroughly. There, Darrell and I describe several important implications related to AI/ET, but chief among them is that these technology developments are on the cusp of ushering in a true revolution in human affairs at an increasingly fast pace. As AI continues to influence and shape existing industries and allows new ones to take root, its macro-level impact, particularly in the realm of economics, will become more and more apparent.