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 Learning Graphical Models


Bayesian Experimental Design for Symbolic Discovery

arXiv.org Artificial Intelligence

This study concerns the formulation and application of Bayesian optimal experimental design to symbolic discovery, which is the inference from observational data of predictive models taking general functional forms. We apply constrained first-order methods to optimize an appropriate selection criterion, using Hamiltonian Monte Carlo to sample from the prior. A step for computing the predictive distribution, involving convolution, is computed via either numerical integration, or via fast transform methods.


Deep representation learning: Fundamentals, Perspectives, Applications, and Open Challenges

arXiv.org Artificial Intelligence

Machine Learning algorithms have had a profound impact on the field of computer science over the past few decades. These algorithms performance is greatly influenced by the representations that are derived from the data in the learning process. The representations learned in a successful learning process should be concise, discrete, meaningful, and able to be applied across a variety of tasks. A recent effort has been directed toward developing Deep Learning models, which have proven to be particularly effective at capturing high-dimensional, non-linear, and multi-modal characteristics. In this work, we discuss the principles and developments that have been made in the process of learning representations, and converting them into desirable applications. In addition, for each framework or model, the key issues and open challenges, as well as the advantages, are examined.


Learning Task-Aware Energy Disaggregation: a Federated Approach

arXiv.org Artificial Intelligence

We consider the problem of learning the energy disaggregation signals for residential load data. Such task is referred as non-intrusive load monitoring (NILM), and in order to find individual devices' power consumption profiles based on aggregated meter measurements, a machine learning model is usually trained based on large amount of training data coming from a number of residential homes. Yet collecting such residential load datasets require both huge efforts and customers' approval on sharing metering data, while load data coming from different regions or electricity users may exhibit heterogeneous usage patterns. Both practical concerns make training a single, centralized NILM model challenging. In this paper, we propose a decentralized and task-adaptive learning scheme for NILM tasks, where nested meta learning and federated learning steps are designed for learning task-specific models collectively. Simulation results on benchmark dataset validate proposed algorithm's performance on efficiently inferring appliance-level consumption for a variety of homes and appliances.


An Anomaly Detection Method for Satellites Using Monte Carlo Dropout

arXiv.org Artificial Intelligence

Recently, there has been a significant amount of interest in satellite telemetry anomaly detection (AD) using neural networks (NN). For AD purposes, the current approaches focus on either forecasting or reconstruction of the time series, and they cannot measure the level of reliability or the probability of correct detection. Although the Bayesian neural network (BNN)-based approaches are well known for time series uncertainty estimation, they are computationally intractable. In this paper, we present a tractable approximation for BNN based on the Monte Carlo (MC) dropout method for capturing the uncertainty in the satellite telemetry time series, without sacrificing accuracy. For time series forecasting, we employ an NN, which consists of several Long Short-Term Memory (LSTM) layers followed by various dense layers. We employ the MC dropout inside each LSTM layer and before the dense layers for uncertainty estimation. With the proposed uncertainty region and by utilizing a post-processing filter, we can effectively capture the anomaly points. Numerical results show that our proposed time series AD approach outperforms the existing methods from both prediction accuracy and AD perspectives.


Evaluating the Perceived Safety of Urban City via Maximum Entropy Deep Inverse Reinforcement Learning

arXiv.org Artificial Intelligence

Inspired by expert evaluation policy for urban perception, we proposed a novel inverse reinforcement learning (IRL) based framework for predicting urban safety and recovering the corresponding reward function. We also presented a scalable state representation method to model the prediction problem as a Markov decision process (MDP) and use reinforcement learning (RL) to solve the problem. Additionally, we built a dataset called SmallCity based on the crowdsourcing method to conduct the research. As far as we know, this is the first time the IRL approach has been introduced to the urban safety perception and planning field to help experts quantitatively analyze perceptual features. Our results showed that IRL has promising prospects in this field. We will later open-source the crowdsourcing data collection site and the model proposed in this paper.


Learning Bimanual Scooping Policies for Food Acquisition

arXiv.org Artificial Intelligence

A robotic feeding system must be able to acquire a variety of foods. Prior bite acquisition works consider single-arm spoon scooping or fork skewering, which do not generalize to foods with complex geometries and deformabilities. For example, when acquiring a group of peas, skewering could smoosh the peas while scooping without a barrier could result in chasing the peas on the plate. In order to acquire foods with such diverse properties, we propose stabilizing food items during scooping using a second arm, for example, by pushing peas against the spoon with a flat surface to prevent dispersion. The added stabilizing arm can lead to new challenges. Critically, this arm should stabilize the food scene without interfering with the acquisition motion, which is especially difficult for easily breakable high-risk food items like tofu. These high-risk foods can break between the pusher and spoon during scooping, which can lead to food waste falling out of the spoon. We propose a general bimanual scooping primitive and an adaptive stabilization strategy that enables successful acquisition of a diverse set of food geometries and physical properties. Our approach, CARBS: Coordinated Acquisition with Reactive Bimanual Scooping, learns to stabilize without impeding task progress by identifying high-risk foods and robustly scooping them using closed-loop visual feedback. We find that CARBS is able to generalize across food shape, size, and deformability and is additionally able to manipulate multiple food items simultaneously. CARBS achieves 87.0% success on scooping rigid foods, which is 25.8% more successful than a single-arm baseline, and reduces food breakage by 16.2% compared to an analytical baseline. Videos can be found at https://sites.google.com/view/bimanualscoop-corl22/home .


Predictive linguistic cues for fake news: a societal artificial intelligence problem

arXiv.org Artificial Intelligence

Media news are making a large part of public opinion and, therefore, must not be fake. News on web sites, blogs, and social media must be analyzed before being published. In this paper, we present linguistic characteristics of media news items to differentiate between fake news and real news using machine learning algorithms. Neural fake news generation, headlines created by machines, semantic incongruities in text and image captions generated by machine are other types of fake news problems. These problems use neural networks which mainly control distributional features rather than evidence. We propose applying correlation between features set and class, and correlation among the features to compute correlation attribute evaluation metric and covariance metric to compute variance of attributes over the news items. Features unique, negative, positive, and cardinal numbers with high values on the metrics are observed to provide a high area under the curve (AUC) and F1-score.


The Fisher-Rao Loss for Learning under Label Noise

arXiv.org Artificial Intelligence

Supervised classification is an important problem in machine learning. Training a classifier (e.g., a deep neural network) can be done by empirical risk minimisation: a numerical optimisation algorithm is applied to find the model parameters that minimise the mean value of a loss function on the training dataset. Choosing a suitable loss function is essential, since different choices can affect the performance of the resulting classifier, as well as the training dynamics. The output of a neural network trained for classification is often interpreted as giving a conditional probability distribution p(y|x) of the class y given the input x, which prompts the use of cross entropy as a loss function [1, 2, 3]. Although originally used for regression problems, the mean squared error is also used as loss function, and several works have compared these two losses [4, 5, 6, 7, 8]. Moreover, the design of new loss functions has been a topic of interest, and those are often tailored for specific problems or contexts, with many different inspirations, such as the correntropy similarity measure [9], the Wasserstein distance [10, 11], and persistent homology [12]. A case of practical interest is when training datasets are corrupted with label noise, i.e., some of the class labels may be incorrect. This is a well-studied problem in machine learning: one of its sources is crowdsourcing labelling, and it can impact the performance of the generated model [13, 14]. Many of the proposed solutions to mitigate this issue involve modifying the learning algorithms and have no theoretical guarantees of robustness.


A Review of Causality for Learning Algorithms in Medical Image Analysis

arXiv.org Artificial Intelligence

Medical image analysis is a vibrant research area that offers doctors and medical practitioners invaluable insight and the ability to accurately diagnose and monitor disease. Machine learning provides an additional boost for this area. However, machine learning for medical image analysis is particularly vulnerable to natural biases like domain shifts that affect algorithmic performance and robustness. In this paper we analyze machine learning for medical image analysis within the framework of Technology Readiness Levels and review how causal analysis methods can fill a gap when creating robust and adaptable medical image analysis algorithms. We review methods using causality in medical imaging AI/ML and find that causal analysis has the potential to mitigate critical problems for clinical translation but that uptake and clinical downstream research has been limited so far.


Visual Place Recognition

arXiv.org Artificial Intelligence

Thus, in this paper, the filter and smoother of Hidden Visual place recognition is a well-defined problem: given Markov Chains were used in place recognition. It is expected an image taken at a certain place, people, animals, computers that the algorithms can avoid the hardware performance or robots should judge whether the corresponding place of the requirements while maintaining high accuracy. It can improve image has been seen before; If it has been seen, where is the computing speed and simplify the complexity of location image taken [1]. This technique provides basic position recognition algorithms. This paper is organized as follows. In information for automatic driving, and its accuracy directly section 1, we introduced the topic of this paper, system determines the safety and accuracy of automatic driving.