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 Statistical Learning


Hierarchy exploitation to detect missing annotations on hierarchical multi-label classification

arXiv.org Artificial Intelligence

The availability of genomic data has grown exponentially in the last decade, mainly due to the development of new sequencing technologies. Based on the interactions between genes (and gene products) extracted from the increasing genomic data, numerous studies have focused on the identification of associations between genes and functions. While these studies have shown great promise, the problem of annotating genes with functions remains an open challenge. In this work, we present a method to detect missing annotations in hierarchical multi-label classification datasets. We propose a method that exploits the class hierarchy by computing aggregated probabilities to the paths of classes from the leaves to the root for each instance. The proposed method is presented in the context of predicting missing gene function annotations, where these aggregated probabilities are further used to select a set of annotations to be verified through in vivo experiments. The experiments on Oriza sativa Japonica, a variety of rice, showcase that incorporating the hierarchy of classes into the method often improves the predictive performance and our proposed method yields superior results when compared to competitor methods from the literature. Genomic data has become exponentially available in the last decade, mainly due to the development of new technologies, including gene expression profiling generated with RNA sequencing (Ranganathan, Gribskov, Nakai and Schรถnbach, 2019). Based on the interactions between genes (and gene products) extracted from the increasing genomic data, numerous studies have focused on the identification of associations between genes and functions (Rust, Mongin and Birney, 2002; Vandepoele, Quimbaya, Casneuf, De Veylder and Van de Peer, 2009; van Dam, Vรตsa, van der Graaf, Franke and de Magalhรฃes, 2017).


Artificial intelligence in cardiovascular medicine

#artificialintelligence

Artificial intelligence (AI) is a rapidly evolving transdisciplinary field employing machine learning (ML) techniques, which aim to simulate human intuition to offer cost-effective and scalable solutions to better manage CVD. ML algorithms are increasingly being developed and applied in various facets of cardiovascular medicine, including and not limited to heart failure, electrophysiology, valvular heart disease and coronary artery disease. Within heart failure, AI algorithms can augment diagnostic capabilities and clinical decision-making through automated cardiac measurements. Occult cardiac disease is increasingly being identified using ML from diagnostic data. Improved diagnostic and prognostic capabilities using ML algorithms are enhancing clinical care of patients with valvular heart disease and coronary artery disease. The growth of AI techniques is not without inherent challenges, most important of which is the need for greater external validation through multicenter, prospective clinical trials.


Logistic Regression in One Picture - DataScienceCentral.com

#artificialintelligence

Logistic regression is regressing data to a line (i.e. This type of regression is a good choice when modeling binary variables, which happen frequently in real life (e.g. The logistic regression model is popular, in part, because it gives probabilities between 0 and 1. Let's say you were modeling a risk of credit default: values closer to 0 indicate a tiny risk, while values closer to 1 mean a very high risk. The following image shows an example of how one might tailor a logistic model for credit score based risk.


Primary Supervised Learning Algorithms Used in Machine Learning - KDnuggets

#artificialintelligence

Supervised learning is a machine learning subset where a machine learning model is trained on labeled (inputs) data. As a result, the supervised model is capable of predicting further outcomes (outputs) as accurately as possible. The concept behind supervised learning can be explained from real-life scenarios such as a teacher tutoring a child about a new topic for the first time. For simplification, let's say that the teacher wants to teach the child to successfully identify the image of a cat and a dog. The teacher will start the tutoring process by continuously showing the child images of either a cat or a dog with the addition of having the teacher inform the child if the image is that of a dog or a cat.


Interpretability in Machine Learning

#artificialintelligence

Should we always trust a model that performs well? A model could reject your application for a mortgage or diagnose you with cancer. The consequences of these decisions are serious and, even if they are correct, we would expect an explanation. A human would be able to tell you that your income is too low for a mortgage or that a specific cluster of cells is likely malignant. A model that provided similar explanations would be more useful than one that just provided predictions. By obtaining these explanations, we say we are interpreting a machine learning model.


FIGS: Attaining XGBoost-level performance with the interpretability and speed of CART

AIHub

Recent machine-learning advances have led to increasingly complex predictive models, often at the cost of interpretability. We often need interpretability, particularly in high-stakes applications such as in clinical decision-making; interpretable models help with all kinds of things, such as identifying errors, leveraging domain knowledge, and making speedy predictions. In this blog post we'll cover FIGS, a new method for fitting an interpretable model that takes the form of a sum of trees. Real-world experiments and theoretical results show that FIGS can effectively adapt to a wide range of structure in data, achieving state-of-the-art performance in several settings, all without sacrificing interpretability. Intuitively, FIGS works by extending CART, a typical greedy algorithm for growing a decision tree, to consider growing a sum of trees simultaneously (see Fig 1).


What are the most in-demand #AI skills? AI implies a lot of deep - LinkedIn

#artificialintelligence

What are the most in-demand #AI skills? AI implies a lot of deep and wide knowledge added up with software and hardware skills. Real AI is not data engineering or #coding and software #engineering skills, in big data tools or developer's skills in Python, R, Java, MATLAB, C, etc., combined with #machinelearning skills. For a real and true and genuine AI, one needs a completely different basic grounding around machine intelligence and learning.


CompoundE: Knowledge Graph Embedding with Translation, Rotation and Scaling Compound Operations

arXiv.org Artificial Intelligence

Translation, rotation, and scaling are three commonly used geometric manipulation operations in image processing. Besides, some of them are successfully used in developing effective knowledge graph embedding (KGE) models such as TransE and RotatE. Inspired by the synergy, we propose a new KGE model by leveraging all three operations in this work. Since translation, rotation, and scaling operations are cascaded to form a compound one, the new model is named CompoundE. By casting CompoundE in the framework of group theory, we show that quite a few scoring-function-based KGE models are special cases of CompoundE. CompoundE extends the simple distance-based relation to relation-dependent compound operations on head and/or tail entities. To demonstrate the effectiveness of CompoundE, we conduct experiments on three popular KG completion datasets. Experimental results show that CompoundE consistently achieves the state of-the-art performance.


Multi-Study Boosting: Theoretical Considerations for Merging vs. Ensembling

arXiv.org Artificial Intelligence

Cross-study replicability is a powerful model evaluation criterion that emphasizes generalizability of predictions. When training cross-study replicable prediction models, it is critical to decide between merging and treating the studies separately. We study boosting algorithms in the presence of potential heterogeneity in predictor-outcome relationships across studies and compare two multi-study learning strategies: 1) merging all the studies and training a single model, and 2) multi-study ensembling, which involves training a separate model on each study and ensembling the resulting predictions. In the regression setting, we provide theoretical guidelines based on an analytical transition point to determine whether it is more beneficial to merge or to ensemble for boosting with linear learners. In addition, we characterize a bias-variance decomposition of estimation error for boosting with component-wise linear learners. We verify the theoretical transition point result in simulation and illustrate how it can guide the decision on merging vs. ensembling in an application to breast cancer gene expression data.


Contextual Bandits with Smooth Regret: Efficient Learning in Continuous Action Spaces

arXiv.org Artificial Intelligence

Designing efficient general-purpose contextual bandit algorithms that work with large -- or even continuous -- action spaces would facilitate application to important scenarios such as information retrieval, recommendation systems, and continuous control. While obtaining standard regret guarantees can be hopeless, alternative regret notions have been proposed to tackle the large action setting. We propose a smooth regret notion for contextual bandits, which dominates previously proposed alternatives. We design a statistically and computationally efficient algorithm -- for the proposed smooth regret -- that works with general function approximation under standard supervised oracles. We also present an adaptive algorithm that automatically adapts to any smoothness level. Our algorithms can be used to recover the previous minimax/Pareto optimal guarantees under the standard regret, e.g., in bandit problems with multiple best arms and Lipschitz/H{\"o}lder bandits. We conduct large-scale empirical evaluations demonstrating the efficacy of our proposed algorithms.