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 Learning Graphical Models


Regression-Based Machine Learning for Algorithmic Trading

@machinelearnbot

Finally, a comprehensive hands-on machine learning course with specific focus on regression based models for the investment community and any passionate investors. In the past few years, there has been a massive adoption and growth in the use of data science, artificial intelligence and machine learning to find alpha. However, information on and application of machine learning to investment are scarce. This course has been designed to address that. It is meant to spark your creative juices.


A Gentle Introduction to Maximum Likelihood Estimation

@machinelearnbot

The first time I heard someone use the term maximum likelihood estimation, I went to Google and found out what it meant. Then I went to Wikipedia to find out what it really meant. To spare you the wrestling required to understand and incorporate MLE into your data science workflow, ethos, and projects, I've compiled this guide. This is funny (if you follow this strange domain of humor), and mostly right about the differences between the two camps. Not minding that our Sun going into nova is not really a repeatable experiment -- sorry, frequentists!


Planning to Give Information in Partially Observed Domains with a Learned Weighted Entropy Model

arXiv.org Artificial Intelligence

In many real-world robotic applications, an autonomous agent must act within and explore a partially observed environment that is unobserved by its human teammate. We consider such a setting in which the agent can, while acting, transmit declarative information to the human that helps them understand aspects of this unseen environment. Importantly, we should expect the human to have preferences about what information they are given and when they are given it. In this work, we adopt an information-theoretic view of the human's preferences: the human scores a piece of information as a function of the induced reduction in weighted entropy of their belief about the environment state. We formulate this setting as a POMDP and give a practical algorithm for solving it approximately. Then, we give an algorithm that allows the agent to sample-efficiently learn the human's preferences online. Finally, we describe an extension in which the human's preferences are time-varying. We validate our approach experimentally in two planning domains: a 2D robot mining task and a more realistic 3D robot fetching task.


Opening the black box of deep learning

arXiv.org Machine Learning

The great success of deep learning shows that its technology contains profound truth, and understanding its internal mechanism not only has important implications for the development of its technology and effective application in various fields, but also provides meaningful insights into the understanding of human brain mechanism. At present, most of the theoretical research on deep learning is based on mathematics. This dissertation proposes that the neural network of deep learning is a physical system, examines deep learning from three different perspectives: microscopic, macroscopic, and physical world views, answers multiple theoretical puzzles in deep learning by using physics principles. For example, from the perspective of quantum mechanics and statistical physics, this dissertation presents the calculation methods for convolution calculation, pooling, normalization, and Restricted Boltzmann Machine, as well as the selection of cost functions, explains why deep learning must be deep, what characteristics are learned in deep learning, why Convolutional Neural Networks do not have to be trained layer by layer, and the limitations of deep learning, etc., and proposes the theoretical direction and basis for the further development of deep learning now and in the future. The brilliance of physics flashes in deep learning, we try to establish the deep learning technology based on the scientific theory of physics.


The Roles of Supervised Machine Learning in Systems Neuroscience

arXiv.org Machine Learning

Over the last several years, the use of machine learning (ML) in neuroscience has been increasing exponentially. Here, we review ML's contributions, both realized and potential, across several areas of systems neuroscience. We describe four primary roles of ML within neuroscience: 1) creating solutions to engineering problems, 2) identifying predictive variables, 3) setting benchmarks for simple models of the brain, and 4) serving itself as a model for the brain. The breadth and ease of its applicability suggests that machine learning should be in the toolbox of most systems neuroscientists.


Learning Maximum-A-Posteriori Perturbation Models for Structured Prediction in Polynomial Time

arXiv.org Machine Learning

MAP perturbation models have emerged as a powerful framework for inference in structured prediction. Such models provide a way to efficiently sample from the Gibbs distribution and facilitate predictions that are robust to random noise. In this paper, we propose a provably polynomial time randomized algorithm for learning the parameters of perturbed MAP predictors. Our approach is based on minimizing a novel Rademacher-based generalization bound on the expected loss of a perturbed MAP predictor, which can be computed in polynomial time. We obtain conditions under which our randomized learning algorithm can guarantee generalization to unseen examples.


Online Learning in Kernelized Markov Decision Processes

arXiv.org Machine Learning

We consider online learning for minimizing regret in unknown, episodic Markov decision processes (MDPs) with continuous states and actions. We develop variants of the UCRL and posterior sampling algorithms that employ nonparametric Gaussian process priors to generalize across the state and action spaces. When the transition and reward functions of the true MDP are either sampled from Gaussian process priors (fully Bayesian setting) or are members of the associated Reproducing Kernel Hilbert Spaces of functions induced by symmetric psd kernels (frequentist setting), we show that the algorithms enjoy sublinear regret bounds. The bounds are in terms of explicit structural parameters of the kernels, namely a novel generalization of the information gain metric from kernelized bandit, and highlight the influence of transition and reward function structure on the learning performance. Our results are applicable to multi-dimensional state and action spaces with composite kernel structures, and generalize results from the literature on kernelized bandits, and the adaptive control of parametric linear dynamical systems with quadratic costs.


Streaming MANN: A Streaming-Based Inference for Energy-Efficient Memory-Augmented Neural Networks

arXiv.org Machine Learning

With the successful development of artificial intelligence using deep learning, there has been growing interest in its deployment. The mobile environment is the closest hardware platform to real life, and it has become an important platform for the success or failure of artificial intelligence. Memory-augmented neural networks (MANNs) are neural networks proposed to efficiently handle question-and-answer (Q&A) tasks, well-suited for mobile devices. As a MANN requires various types of operations and recurrent data paths, it is difficult to accelerate the inference in the structure designed for other conventional neural network models, which is one of the biggest obstacles to deploying MANNs in mobile environments. To address the aforementioned issues, we propose Streaming MANN. This is the first attempt to implement and demonstrate the architecture for energy-efficient inference of MANNs with the concept of streaming processing. To achieve the full potential of the streaming process, we propose a novel approach, called inference thresholding, using Bayesian approach considering the characteristics of natural language processing (NLP) tasks. To evaluate our proposed approaches, we implemented the architecture and method in a field-programmable gate array (FPGA) which is suitable for streaming processing. We measured the execution time and power consumption of the inference for the bAbI dataset. The experimental results showed that the performance efficiency per energy (FLOPS/kJ) of the Streaming MANN increased by a factor of up to about 126 compared to the results of NVIDIA TITAN V, and up to 140 if inference thresholding is applied.


Transductive Boltzmann Machines

arXiv.org Machine Learning

We present transductive Boltzmann machines (TBMs), which firstly achieve transductive learning of the Gibbs distribution. While exact learning of the Gibbs distribution is impossible by the family of existing Boltzmann machines due to combinatorial explosion of the sample space, TBMs overcome the problem by adaptively constructing the minimum required sample space from data to avoid unnecessary generalization. We theoretically provide bias-variance decomposition of the KL divergence in TBMs to analyze its learnability, and empirically demonstrate that TBMs are superior to the fully visible Boltzmann machines and popularly used restricted Boltzmann machines in terms of efficiency and effectiveness.


Guided Feature Transformation (GFT): A Neural Language Grounding Module for Embodied Agents

arXiv.org Artificial Intelligence

Recently there has been a rising interest in training agents, embodied in virtual environments, to perform language-directed tasks by deep reinforcement learning. In this paper, we propose a simple but effective neural language grounding module for embodied agents that can be trained end to end from scratch taking raw pixels, unstructured linguistic commands, and sparse rewards as the inputs. We model the language grounding process as a language-guided transformation of visual features, where latent sentence embeddings are used as the transformation matrices. In several language-directed navigation tasks that feature challenging partial observation and require simple reasoning, our module significantly outperforms the state of the arts. We also release XWORLD 3D, an easy-to-customize 3D environment that can potentially be modified to evaluate a variety of embodied agents.