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 Deep Learning


Epistemic Neural Networks

arXiv.org Artificial Intelligence

We introduce the \textit{epistemic neural network} (ENN) as an interface for uncertainty modeling in deep learning. All existing approaches to uncertainty modeling can be expressed as ENNs, and any ENN can be identified with a Bayesian neural network. However, this new perspective provides several promising directions for future research. Where prior work has developed probabilistic inference tools for neural networks; we ask instead, `which neural networks are suitable as tools for probabilistic inference?'. We propose a clear and simple metric for progress in ENNs: the KL-divergence with respect to a target distribution. We develop a computational testbed based on inference in a neural network Gaussian process and release our code as a benchmark at \url{https://github.com/deepmind/enn}. We evaluate several canonical approaches to uncertainty modeling in deep learning, and find they vary greatly in their performance. We provide insight to the sensitivity of these results and show that our metric is highly correlated with performance in sequential decision problems. Finally, we provide indications that new ENN architectures can improve performance in both the statistical quality and computational cost.


Multimodal Reward Shaping for Efficient Exploration in Reinforcement Learning

arXiv.org Artificial Intelligence

Maintaining long-term exploration ability remains one of the challenges of deep reinforcement learning (DRL). In practice, the reward shaping-based approaches are leveraged to provide intrinsic rewards for the agent to incentivize motivation. However, most existing IRS modules rely on attendant models or additional memory to record and analyze learning procedures, which leads to high computational complexity and low robustness. Moreover, they overemphasize the influence of a single state on exploration, which cannot evaluate the exploration performance from a global perspective. To tackle the problem, state entropy-based methods are proposed to encourage the agent to visit the state space more equitably. However, the estimation error and sample complexity are prohibitive when handling environments with high-dimensional observation. In this paper, we introduce a novel metric entitled Jain's fairness index (JFI) to replace the entropy regularizer, which requires no additional models or memory. In particular, JFI overcomes the vanishing intrinsic rewards problem and can be generalized into arbitrary tasks. Furthermore, we use a variational auto-encoder (VAE) model to capture the life-long novelty of states. Finally, the global JFI score and local state novelty are combined to form a multimodal intrinsic reward, controlling the exploration extent more precisely. Finally, extensive simulation results demonstrate that our multimodal reward shaping (MMRS) method can achieve higher performance in contrast to other benchmark schemes.


CETransformer: Casual Effect Estimation via Transformer Based Representation Learning

arXiv.org Artificial Intelligence

Treatment effect estimation, which refers to the estimation of causal effects and aims to measure the strength of the causal relationship, is of great importance in many fields but is a challenging problem in practice. As present, data-driven causal effect estimation faces two main challenges, i.e., selection bias and the missing of counterfactual. To address these two issues, most of the existing approaches tend to reduce the selection bias by learning a balanced representation, and then to estimate the counterfactual through the representation. However, they heavily rely on the finely hand-crafted metric functions when learning balanced representations, which generally doesn't work well for the situations where the original distribution is complicated. In this paper, we propose a CETransformer model for casual effect estimation via transformer based representation learning. To learn the representation of covariates(features) robustly, a self-supervised transformer is proposed, by which the correlation between covariates can be well exploited through self-attention mechanism. In addition, an adversarial network is adopted to balance the distribution of the treated and control groups in the representation space. Experimental results on three real-world datasets demonstrate the advantages of the proposed CETransformer, compared with the state-of-the-art treatment effect estimation methods.


Interpreting Process Predictions using a Milestone-Aware Counterfactual Approach

arXiv.org Artificial Intelligence

Predictive process analytics often apply machine learning to predict the future states of a running business process. However, the internal mechanisms of many existing predictive algorithms are opaque and a human decision-maker is unable to understand \emph{why} a certain activity was predicted. Recently, counterfactuals have been proposed in the literature to derive human-understandable explanations from predictive models. Current counterfactual approaches consist of finding the minimum feature change that can make a certain prediction flip its outcome. Although many algorithms have been proposed, their application to the sequence and multi-dimensional data like event logs has not been explored in the literature. In this paper, we explore the use of a recent, popular model-agnostic counterfactual algorithm, DiCE, in the context of predictive process analytics. The analysis reveals that the algorithm is limited when being applied to derive explanations of process predictions, due to (1) process domain knowledge not being taken into account, (2) long traces that often tend to be less understandable, and (3) difficulties in optimising the counterfactual search with categorical variables. We design an extension of DiCE that can generate counterfactuals for process predictions, and propose an approach that supports deriving milestone-aware counterfactuals at different stages of a trace to promote interpretability. We apply our approach to BPIC2012 event log and the analysis results demonstrate the effectiveness of the proposed approach.


Facial Expressions Recognition with Convolutional Neural Networks

arXiv.org Artificial Intelligence

Over the centuries, humans have developed and acquired a number of ways to communicate. But hardly any of them can be as natural and instinctive as facial expressions. On the other hand, neural networks have taken the world by storm. And no surprises, that the area of Computer Vision and the problem of facial expressions recognitions hasn't remained untouched. Although a wide range of techniques have been applied, achieving extremely high accuracies and preparing highly robust FER systems still remains a challenge due to heterogeneous details in human faces. In this paper, we will be deep diving into implementing a system for recognition of facial expressions (FER) by leveraging neural networks, and more specifically, Convolutional Neural Networks (CNNs). We adopt the fundamental concepts of deep learning and computer vision with various architectures, fine-tune it's hyperparameters and experiment with various optimization methods and demonstrate a state-of-the-art single-network-accuracy of 70.10% on the FER2013 dataset without using any additional training data.


OpenAI Codex shows the limits of large language models

#artificialintelligence

All the sessions from Transform 2021 are available on-demand now. In a new paper, researchers at OpenAI have revealed details about Codex, a deep learning model that generates software source code. Codex powers Copilot, an "AI pair programmer" tool developed jointly by OpenAI and GitHub. Copilot is currently available in beta test mode to a limited number of users. The paper is a fascinating read that explains the process through which the scientists at OpenAI managed to repurpose their flagship language model GPT-3 to create Codex. But more importantly, the paper also sheds much-needed light on how far you can trust deep learning in programming.


Artificial Intelligence: PowerSecure on the Future of the Microgrid

#artificialintelligence

Marshall Worth, senior project manager AI at PowerSecure, discusses artificial intelligence and a practical approach that microgrid customers can take today to achieve their energy goals of the future. With as fast as technology has progressed over the last decade, and with the promise of self-driving cars on the horizon and the electrification of everything, it's only natural to question when this is all going to filter into our everyday, energy consuming lives. In this device-driven age, shouldn't we already have the artificial intelligence (AI) capabilities to reduce our carbon footprint today and our energy bill tomorrow? Those of us who work in the energy industry are fortunate; we are naturally driven to innovate and build the future of energy. However, it's a bit ambitious to think that the same machine that drives our car and controls our thermostat today can also manage on-site generating assets.


Mercari Price Prediction Challenge

#artificialintelligence

Mercari is an e-commerce company currently operational in the US and Japan. This provides a platform where customers can sell items that are no longer useful. It tries to make all the processes hassle-free by providing at-home pickups, same-day delivery, and many other advantages. The company website displays more than 350k items are listed every day on the website which reflects its popularity among users. Mercari is an e-commerce company currently operational in the US and Japan. This provides a platform where customers can sell items that are no longer useful. It tries to make all the processes hassle-free by providing at-home pickups, same-day delivery, and many other advantages. The company website displays more than 350k items are listed every day on the website which reflects its popularity among users.


Audio Clustering with Deep Learning

#artificialintelligence

Deep neural networks are popular for various image processing or NLP tasks. In recent times, however, research focused on audio tasks using deep learning techniques has seen a surge. Some of the deep learning techniques have been adopted from image processing tasks, however audios are quite different as they are one-dimensional time series signal which is different from two-dimensional images. Deep learning methods with audio as input are important as audio is a very prevalent medium in our daily lives. In this project, the main objective was to train a deep neural network for the purpose of feature extraction, clustering or both.


Natural language understanding tough for neural networks

#artificialintelligence

All the sessions from Transform 2021 are available on-demand now. One of the dominant trends of artificial intelligence in the past decade has been to solve problems by creating ever-larger deep learning models. And nowhere is this trend more evident than in natural language processing, one of the most challenging areas of AI. In recent years, researchers have shown that adding parameters to neural networks improves their performance on language tasks. However, the fundamental problem of understanding language--the iceberg lying under words and sentences--remains unsolved.