Learning Graphical Models
A general framework for causal classification
Li, Jiuyong, Zhang, Weijia, Liu, Lin, Yu, Kui, Le, Thuc Duy, Liu, Jixue
In many applications, there is a need to predict the effect of an intervention on different individuals from data. For example, which customers are persuadable by a product promotion? which groups would benefit from a new policy? These are typical causal classification questions involving the effect or the change in outcomes made by an intervention. The questions cannot be answered with traditional classification methods as they only deal with static outcomes. In marketing research these questions are often answered with uplift modelling, using experimental data. Some machine learning methods have been proposed for heterogeneous causal effect estimation using either experimental or observational data. In principle these methods can be used for causal classification, but a limited number of methods, mainly tree based, on causal heterogeneity modelling, are inadequate for various real world applications. In this paper, we propose a general framework for causal classification, as a generalisation of both uplift modelling and causal heterogeneity modelling. When developing the framework, we have identified the conditions where causal classification in both observational and experimental data can be resolved by a naive solution using off-the-shelf classification methods, which supports flexible implementations for various applications. This result not only enables a practical way to solve the causal classification problem by using any existing classification method in the proposed framework, but also makes it possible to cross use the methods developed in both uplift modelling and causal heterogeneity modelling areas when the conditions are satisfied. Experiments have shown that our framework with off-the-shelf classification methods is as competitive as the tailor-designed uplift modelling and heterogeneous causal effect modelling methods.
BayesFlow: Learning complex stochastic models with invertible neural networks
Radev, Stefan T., Mertens, Ulf K., Voss, Andreass, Ardizzone, Lynton, Köthe, Ullrich
Estimating the parameters of mathematical models is a common problem in almost all branches of science. However, this problem can prove notably difficult when processes and model descriptions become increasingly complex and an explicit likelihood function is not available. With this work, we propose a novel method for globally amortized Bayesian inference based on invertible neural networks which we call BayesFlow. The method uses simulation to learn a global estimator for the probabilistic mapping from observed data to underlying model parameters. A neural network pre-trained in this way can then, without additional training or optimization, infer full posteriors on arbitrary many real data sets involving the same model family. In addition, our method incorporates a summary network trained to embed the observed data into maximally informative summary statistics. Learning summary statistics from data makes the method applicable to modeling scenarios where standard inference techniques with hand-crafted summary statistics fail. We demonstrate the utility of BayesFlow on challenging intractable models from population dynamics, epidemiology, cognitive science and ecology. We argue that BayesFlow provides a general framework for building reusable Bayesian parameter estimation machines for any process model from which data can be simulated.
A Survey on Edge Intelligence
Xu, Dianlei, Li, Tong, Li, Yong, Su, Xiang, Tarkoma, Sasu, Hui, Pan
Edge intelligence refers to a set of connected systems and devices for data collection, caching, processing, and analysis in locations close to where data is captured based on artificial intelligence. The aim of edge intelligence is to enhance the quality and speed of data processing and protect the privacy and security of the data. Although recently emerged, spanning the period from 2011 to now, this field of research has shown explosive growth over the past five years. In this paper, we present a thorough and comprehensive survey on the literature surrounding edge intelligence. We first identify four fundamental components of edge intelligence, namely edge caching, edge training, edge inference, and edge offloading, based on theoretical and practical results pertaining to proposed and deployed systems. We then aim for a systematic classification of the state of the solutions by examining research results and observations for each of the four components and present a taxonomy that includes practical problems, adopted techniques, and application goals. For each category, we elaborate, compare and analyse the literature from the perspectives of adopted techniques, objectives, performance, advantages and drawbacks, etc. This survey article provides a comprehensive introduction to edge intelligence and its application areas. In addition, we summarise the development of the emerging research field and the current state-of-the-art and discuss the important open issues and possible theoretical and technical solutions.
Too many cooks: Coordinating multi-agent collaboration through inverse planning
Wang, Rose E., Wu, Sarah A., Evans, James A., Tenenbaum, Joshua B., Parkes, David C., Kleiman-Weiner, Max
Collaboration requires agents to coordinate their behavior on the fly, sometimes cooperating to solve a single task together and other times dividing it up into sub-tasks to work on in parallel. Underlying the human ability to collaborate is theory-of-mind, the ability to infer the hidden mental states that drive others to act. Here, we develop Bayesian Delegation, a decentralized multi-agent learning mechanism with these abilities. Bayesian Delegation enables agents to rapidly infer the hidden intentions of others by inverse planning. These inferences enable agents to flexibly decide in the absence of communication when to cooperate on the same sub-task and when to work on different sub-tasks in parallel. We test this model in a suite of multi-agent Markov decision processes inspired by cooking problems. To succeed, agents must coordinate both their high-level plans (e.g., what sub-task they should work on) and their low-level actions (e.g., avoiding collisions). Bayesian Delegation bridges these two levels and rapidly aligns agents' beliefs about who should work on what without any communication. When agents cooperate on the same sub-task, coordinated plans emerge that enable the group of agents to achieve tasks no agent can complete on their own. Our model outperforms lesioned agents without Bayesian Delegation or without the ability to cooperate on the same sub-task.
What is Bayes Theorem?
If you've been learning about data science or machine learning, there's a good chance you've heard the term "Bayes Theorem" before, or a "Bayes classifier". These concepts can be somewhat confusing, especially if you aren't used to thinking of probability from a traditional, frequentist statistics perspective. This article will attempt to explain the principles behind Bayes Theorem and how it's used in machine learning. Bayes Theorem is a method of calculating conditional probability. The traditional method of calculating conditional probability (the probability that one event occurs given the occurrence of a different event) is to use the conditional probability formula, calculating the joint probability of event one and event two occurring at the same time, and then dividing it by the probability of event two occurring.
Glioma stages prediction based on machine learning algorithm combined with protein-protein interaction networks
In this study recently published in Genomics, the author team aimed to characterize molecular mechanisms associated with glioma progression stages by using machine learning and protein-protein interaction networks analysis. Background: Glioma is the most lethal nervous system cancer. Recent studies have made great efforts to study the occurrence and development of glioma, but the molecular mechanisms are still unclear. This study was designed to reveal the molecular mechanisms of glioma based on protein-protein interaction network combined with machine learning methods. Key differentially expressed genes (DEGs) were screened and selected by using the protein-protein interaction (PPI) networks.
A Critique on the Interventional Detection of Causal Relationships
Interventions are of fundamental importance in Pearl's probabilistic causality regime. In this paper, we will inspect how interventions influence the interpretation of causation in causal models in specific situation. To this end, we will introduce a priori relationships as non-causal relationships in a causal system. Then, we will proceed to discuss the cases that interventions can lead to spurious causation interpretations. This includes the interventional detection of a priori relationships, and cases where the interventional detection of causality forms structural causal models that are not valid in natural situations. We will also discuss other properties of a priori relations and SCMs that have a priori information in their structural equations.
Interval Neural Networks: Uncertainty Scores
Oala, Luis, Heiß, Cosmas, Macdonald, Jan, März, Maximilian, Samek, Wojciech, Kutyniok, Gitta
We propose a fast, non-Bayesian method for producing uncertainty scores in the output of pre-trained deep neural networks (DNNs) using a data-driven interval propagating network. This interval neural network (INN) has interval valued parameters and propagates its input using interval arithmetic. The INN produces sensible lower and upper bounds encompassing the ground truth. We provide theoretical justification for the validity of these bounds. Furthermore, its asymmetric uncertainty scores offer additional, directional information beyond what Gaussian-based, symmetric variance estimation can provide. We find that noise in the data is adequately captured by the intervals produced with our method. In numerical experiments on an image reconstruction task, we demonstrate the practical utility of INNs as a proxy for the prediction error in comparison to two state-of-the-art uncertainty quantification methods. In summary, INNs produce fast, theoretically justified uncertainty scores for DNNs that are easy to interpret, come with added information and pose as improved error proxies - features that may prove useful in advancing the usability of DNNs especially in sensitive applications such as health care.
Scalable Variational Gaussian Process Regression Networks
Li, Shibo, Xing, Wei, Kirby, Mike, Zhe, Shandian
Gaussian process regression networks (GPRN) are powerful Bayesian models for multi-output regression, but their inference is intractable. To address this issue, existing methods use a fully factorized structure (or a mixture of such structures) over all the outputs and latent functions for posterior approximation, which, however, can miss the strong posterior dependencies among the latent variables and hurt the inference quality. In addition, the updates of the variational parameters are inefficient and can be prohibitively expensive for a large number of outputs. To overcome these limitations, we propose a scalable variational inference algorithm for GPRN, which not only captures the abundant posterior dependencies but also is much more efficient for massive outputs. We tensorize the output space and introduce tensor/matrix-normal variational posteriors to capture the posterior correlations and to reduce the parameters. We jointly optimize all the parameters and exploit the inherent Kronecker product structure in the variational model evidence lower bound to accelerate the computation. We demonstrate the advantages of our method in several real-world applications.
Bayesian Sparsification Methods for Deep Complex-valued Networks
Nazarov, Ivan, Burnaev, Evgeny
Deep neural networks are an integral part of machine learning and data science toolset for practical data-driven problem solving. With continual miniaturization ever more applications can be found in embedded systems. Common embedded applications include on-device image recognition and signal processing. Despite recent advances in generalization and optimization theory specific to deep networks, deploying in actual embedded hardware remains a challenge due to storage, real-time throughput, and arithmetic complexity restrictions [He et al., 2018]. Therefore, compression methods for achieving high model sparsity and numerical efficiency without losing much in performance are especially relevant.