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Learning Disentangled Semantic Spaces of Explanations via Invertible Neural Networks

arXiv.org Artificial Intelligence

Disentangling sentence representations over continuous spaces can be a critical process in improving interpretability and semantic control by localising explicit generative factors. Such process confers to neural-based language models some of the advantages that are characteristic of symbolic models, while keeping their flexibility. This work presents a methodology for disentangling the hidden space of a BERT-GPT2 autoencoder by transforming it into a more separable semantic space with the support of a flow-based invertible neural network (INN). Experimental results indicate that the INN can transform the distributed hidden space into a better semantically disentangled latent space, resulting in better interpretability and controllability, when compared to recent state-of-the-art models.


Single-model uncertainty quantification in neural network potentials does not consistently outperform model ensembles

arXiv.org Artificial Intelligence

Neural networks (NNs) often assign high confidence to their predictions, even for points far out-of-distribution, making uncertainty quantification (UQ) a challenge. When they are employed to model interatomic potentials in materials systems, this problem leads to unphysical structures that disrupt simulations, or to biased statistics and dynamics that do not reflect the true physics. Differentiable UQ techniques can find new informative data and drive active learning loops for robust potentials. However, a variety of UQ techniques, including newly developed ones, exist for atomistic simulations and there are no clear guidelines for which are most effective or suitable for a given case. In this work, we examine multiple UQ schemes for improving the robustness of NN interatomic potentials (NNIPs) through active learning. In particular, we compare incumbent ensemble-based methods against strategies that use single, deterministic NNs: mean-variance estimation, deep evidential regression, and Gaussian mixture models. We explore three datasets ranging from in-domain interpolative learning to more extrapolative out-of-domain generalization challenges: rMD17, ammonia inversion, and bulk silica glass. Performance is measured across multiple metrics relating model error to uncertainty. Our experiments show that none of the methods consistently outperformed each other across the various metrics. Ensembling remained better at generalization and for NNIP robustness; MVE only proved effective for in-domain interpolation, while GMM was better out-of-domain; and evidential regression, despite its promise, was not the preferable alternative in any of the cases. More broadly, cost-effective, single deterministic models cannot yet consistently match or outperform ensembling for uncertainty quantification in NNIPs.


Tesla's Magnet Mystery Shows Elon Musk Is Willing to Compromise

WIRED

To magneticians, folks who study the uncanny forces some materials exert thanks to the movements of electrons and sometimes use cryptic hand gestures, the identity of Rare Earth 1 was obvious: neodymium. When added to more familiar elements, like iron and boron, the metal can help create a powerful, always-on magnetic field. But few materials have this quality. And even fewer generate a field that is strong enough to move a 4,500-pound Tesla--and lots of other things, from industrial robots to fighter jets. If Tesla planned to eliminate neodymium and other rare earths from its motors, what sort of magnets would it use instead?


Physics-constrained neural differential equations for learning multi-ionic transport

arXiv.org Artificial Intelligence

Continuum models for ion transport through polyamide nanopores require solving partial differential equations (PDEs) through complex pore geometries. Resolving spatiotemporal features at this length and time-scale can make solving these equations computationally intractable. In addition, mechanistic models frequently require functional relationships between ion interaction parameters under nano-confinement, which are often too challenging to measure experimentally or know a priori. In this work, we develop the first physics-informed deep learning model to learn ion transport behaviour across polyamide nanopores. The proposed architecture leverages neural differential equations in conjunction with classical closure models as inductive biases directly encoded into the neural framework. The neural differential equations are pre-trained on simulated data from continuum models and fine-tuned on independent experimental data to learn ion rejection behaviour. Gaussian noise augmentations from experimental uncertainty estimates are also introduced into the measured data to improve model generalization. Our approach is compared to other physics-informed deep learning models and shows strong agreement with experimental measurements across all studied datasets.


Design and Evaluation of a Bioinspired Tendon-Driven 3D-Printed Robotic Eye with Active Vision Capabilities

arXiv.org Artificial Intelligence

The field of robotics has seen significant advancements in recent years, particularly in the development of humanoid robots. One area of research that has yet to be fully explored is the design of robotic eyes. In this paper, we propose a computer-aided 3D design scheme for a robotic eye that incorporates realistic appearance, natural movements, and efficient actuation. The proposed design utilizes a tendon-driven actuation mechanism, which offers a broad range of motion capabilities. The use of the minimum number of servos for actuation, one for each agonist-antagonist pair of muscles, makes the proposed design highly efficient. Compared to existing ones in the same class, our designed robotic eye comprises aesthetic and realistic features. We evaluate the robot's performance using a vision-based controller, which demonstrates the effectiveness of the proposed design in achieving natural movement, and efficient actuation. The experiment code, toolbox, and printable 3D sketches of our design have been open-sourced.


The ART of Transfer Learning: An Adaptive and Robust Pipeline

arXiv.org Artificial Intelligence

Transfer learning is an essential tool for improving the performance of primary tasks by leveraging information from auxiliary data resources. In this work, we propose Adaptive Robust Transfer Learning (ART), a flexible pipeline of performing transfer learning with generic machine learning algorithms. We establish the non-asymptotic learning theory of ART, providing a provable theoretical guarantee for achieving adaptive transfer while preventing negative transfer. Additionally, we introduce an ART-integrated-aggregating machine that produces a single final model when multiple candidate algorithms are considered. We demonstrate the promising performance of ART through extensive empirical studies on regression, classification, and sparse learning. We further present a real-data analysis for a mortality study.


An Extensible Multimodal Multi-task Object Dataset with Materials

arXiv.org Artificial Intelligence

We present EMMa, an Extensible, Multimodal dataset of Amazon product listings that contains rich Material annotations. It contains more than 2.8 million objects, each with image(s), listing text, mass, price, product ratings, and position in Amazon's product-category taxonomy. Objects are annotated with one or more materials from this taxonomy. With the numerous attributes available for each object, we develop a Smart Labeling framework to quickly add new binary labels to all objects with very little manual labeling effort, making the dataset extensible. Each object attribute in our dataset can be included in either the model inputs or outputs, leading to combinatorial possibilities in task configurations. For example, we can train a model to predict the object category from the listing text, or the mass and price from the product listing image. EMMa offers a new benchmark for multi-task learning in computer vision and NLP, and allows practitioners to efficiently add new tasks and object attributes at scale. Perhaps the biggest problem faced by machine learning practitioners today is that of producing labeled datasets for their specific needs. Manually labeling large amounts of data is time-consuming and costly (Deng et al., 2009; Lin et al., 2014; Kuznetsova et al., 2020). Furthermore, it is often not possible to communicate how numerous ambiguous corner cases should be handled (e.g., is a hole puncher "sharp"?) to the human annotators we typically rely on to produce these labels. Could we solve this problem with the aid of machine learning? We hypothesized that we could accurately add new properties to every instance in a semi-automated fashion if given a rich dataset with substantial information about every instance. Consequently, we developed EMMa, a large, object-centric, multimodal, and multi-task dataset. We show that EMMa can be easily extended to contain any number of new object labels using a Smart Labeling technique we developed for large multi-task and multimodal datasets. Multi-task datasets contain labels for more than one attribute for each instance, whereas multimodal datasets contain data from more than one modality, such as images, text, audio, and tabular data. Derived from Amazon product listings, EMMa contains images, text, and a number of useful attributes, such as materials, mass, price, product category, and product ratings. Each attribute can be used as either a model input or a model output.


Leveraging Data Mining Algorithms to Recommend Source Code Changes

arXiv.org Artificial Intelligence

Context: Recent research has used data mining to develop techniques that can guide developers through source code changes. To the best of our knowledge, very few studies have investigated data mining techniques and--or compared their results with other algorithms or a baseline. Objectives: This paper proposes an automatic method for recommending source code changes using four data mining algorithms. We not only use these algorithms to recommend source code changes, but we also conduct an empirical evaluation. Methods: Our investigation includes seven open-source projects from which we extracted source change history at the file level. We used four widely data mining algorithms \ie{} Apriori, FP-Growth, Eclat, and Relim to compare the algorithms in terms of performance (Precision, Recall and F-measure) and execution time. Results: Our findings provide empirical evidence that while some Frequent Pattern Mining algorithms, such as Apriori may outperform other algorithms in some cases, the results are not consistent throughout all the software projects, which is more likely due to the nature and characteristics of the studied projects, in particular their change history. Conclusion: Apriori seems appropriate for large-scale projects, whereas Eclat appears to be suitable for small-scale projects. Moreover, FP-Growth seems an efficient approach in terms of execution time.


Artificial Intelligence in Material Engineering: A review on applications of AI in Material Engineering

arXiv.org Artificial Intelligence

The role of artificial intelligence (AI) in material science and engineering (MSE) is becoming increasingly important as AI technology advances. The development of high-performance computing has made it possible to test deep learning (DL) models with significant parameters, providing an opportunity to overcome the limitation of traditional computational methods, such as density functional theory (DFT), in property prediction. Machine learning (ML)-based methods are faster and more accurate than DFT-based methods. Furthermore, the generative adversarial networks (GANs) have facilitated the generation of chemical compositions of inorganic materials without using crystal structure information. These developments have significantly impacted material engineering (ME) and research. Some of the latest developments in AI in ME herein are reviewed. First, the development of AI in the critical areas of ME, such as in material processing, the study of structure and material property, and measuring the performance of materials in various aspects, is discussed. Then, the significant methods of AI and their uses in MSE, such as graph neural network, generative models, transfer of learning, etc. are discussed. The use of AI to analyze the results from existing analytical instruments is also discussed. Finally, AI's advantages, disadvantages, and future in ME are discussed.


Do Embodied Agents Dream of Pixelated Sheep: Embodied Decision Making using Language Guided World Modelling

arXiv.org Artificial Intelligence

Reinforcement learning (RL) agents typically learn tabula rasa, without prior knowledge of the world. However, if initialized with knowledge of high-level subgoals and transitions between subgoals, RL agents could utilize this Abstract World Model (AWM) for planning and exploration. We propose using few-shot large language models (LLMs) to hypothesize an AWM, that will be verified through world experience, to improve sample efficiency of RL agents. Our DECKARD agent applies LLM-guided exploration to item crafting in Minecraft in two phases: (1) the Dream phase where the agent uses an LLM to decompose a task into a sequence of subgoals, the hypothesized AWM; and (2) the Wake phase where the agent learns a modular policy for each subgoal and verifies or corrects the hypothesized AWM. Our method of hypothesizing an AWM with LLMs and then verifying the AWM based on agent experience not only increases sample efficiency over contemporary methods by an order of magnitude but is also robust to and corrects errors in the LLM, successfully blending noisy internet-scale information from LLMs with knowledge grounded in environment dynamics.