Statistical Learning
Global Trend in Artificial Intelligence–Based Publications in Radiology From 2000 to 2018 : American Journal of Roentgenology : Vol. 213, No. 6 (AJR)
All publication searches were performed using a comprehensive central database (Web of Science Core Collection, Clarivate Analytics) that searches the world's leading scholarly journals and proceedings in the sciences and includes the MEDLINE and PubMed databases. From 2000 to 2018, all AI-related publications were selected using the following search terms: "artificial intelligence," "AI," "CNN," "CNNs," "ANN," "ANNs," "neural network," "neural networks," "machine learning," "deep learning," "computer learning," "support vector machine," "support vector machines," "Bayesian network," "Bayesian networks," "cluster analysis," "feature learning," "feature extraction," and "principal components analysis." Radiology-specific AI research was selected using the predefined database category "Radiology Nuclear Medicine Medical Imaging." The resulting publication database was then categorized by country of origin, funding agencies, organizations, publication type, and journal. Nine radiology subspecialty publications were evaluated using the following search terms.
Artificial Intelligence & the Future - Rise of AI (Elon Musk, Bill Gates, Sundar Pichai) Simplilearn
Artificial Intelligence (AI) is currently the hottest buzzword in tech. Here is a video on the role of Artificial Intelligence and its scope in the future. We have put together the best clips on Artificial Intelligence by the most well-known leaders and influencers such as Bill Gates, Tim Cook, Warren Buffett, Barack Obama, Elon Musk, Sundar Pichai and Jeff Bezos. The last few years have seen a number of techniques that have previously been in the realm of science fiction slowly transform into reality. We have brought to you the business leaders of today speaking about artificial intelligence, what is fascinating about AI, the latest AI projects and what's in store for the future of AI.
Learn classification algorithms using Python and scikit-learn
This tutorial is part of the Machine learning for developers learning path. In this tutorial, we describe the basics of solving a classification-based machine learning problem, and give you a comparative study of some of the current most popular algorithms. In the open Notebook, click Run to run the cells one at a time. The rest of the tutorial follows the order of the Notebook. Classification is when the feature to be predicted contains categories of values.
Surveying the reach and maturity of machine learning and artificial intelligence in astronomy
Machine learning (automated processes that learn by example in order to classify, predict, discover or generate new data) and artificial intelligence (methods by which a computer makes decisions or discoveries that would usually require human intelligence) are now firmly established in astronomy. Every week, new applications of machine learning and artificial intelligence are added to a growing corpus of work. Random forests, support vector machines, and neural networks (artificial, deep, and convolutional) are now having a genuine impact for applications as diverse as discovering extrasolar planets, transient objects, quasars, and gravitationally-lensed systems, forecasting solar activity, and distinguishing between signals and instrumental effects in gravitational wave astronomy. This review surveys contemporary, published literature on machine learning and artificial intelligence in astronomy and astrophysics. Applications span seven main categories of activity: classification, regression, clustering, forecasting, generation, discovery, and the development of new scientific insight.
Deep Relevance Regularization: Interpretable and Robust Tumor Typing of Imaging Mass Spectrometry Data
Etmann, Christian, Schmidt, Maximilian, Behrmann, Jens, Boskamp, Tobias, Hauberg-Lotte, Lena, Peter, Annette, Casadonte, Rita, Kriegsmann, Jörg, Maass, Peter
Neural networks have recently been established as a viable classification method for imaging mass spectrometry data for tumor typing. For multi-laboratory scenarios however, certain confounding factors may strongly impede their performance. In this work, we introduce Deep Relevance Regularization, a method of restricting what the neural network can focus on during classification, in order to improve the classification performance. We demonstrate how Deep Relevance Regularization robustifies neural networks against confounding factors on a challenging inter-lab dataset consisting of breast and ovarian carcinoma. We further show that this makes the relevance map - a way of visualizing the discriminative parts of the mass spectrum - sparser, thereby making the classifier easier to interpret.
Transfer Learning-Based Outdoor Position Recovery with Telco Data
Zhang, Yige, Ding, Aaron Yi, Ott, Jorg, Yuan, Mingxuan, Zeng, Jia, Zhang, Kun, Rao, Weixiong
Telecommunication (Telco) outdoor position recovery aims to localize outdoor mobile devices by leveraging measurement report (MR) data. Unfortunately, Telco position recovery requires sufficient amount of MR samples across different areas and suffers from high data collection cost. For an area with scarce MR samples, it is hard to achieve good accuracy. In this paper, by leveraging the recently developed transfer learning techniques, we design a novel Telco position recovery framework, called TLoc, to transfer good models in the carefully selected source domains (those fine-grained small subareas) to a target one which originally suffers from poor localization accuracy. Specifically, TLoc introduces three dedicated components: 1) a new coordinate space to divide an area of interest into smaller domains, 2) a similarity measurement to select best source domains, and 3) an adaptation of an existing transfer learning approach. To the best of our knowledge, TLoc is the first framework that demonstrates the efficacy of applying transfer learning in the Telco outdoor position recovery. To exemplify, on the 2G GSM and 4G LTE MR datasets in Shanghai, TLoc outperforms a nontransfer approach by 27.58% and 26.12% less median errors, and further leads to 47.77% and 49.22% less median errors than a recent fingerprinting approach NBL.
Towards a Robust Classifier: An MDL-Based Method for Generating Adversarial Examples
Asadi, Behzad, Varadharajan, Vijay
We address the problem of adversarial examples in machine learning where an adversary tries to misguide a classifier by making functionality-preserving modifications to original samples. We assume a black-box scenario where the adversary has access to only the feature set, and the final hard-decision output of the classifier. We propose a method to generate adversarial examples using the minimum description length (MDL) principle. Our final aim is to improve the robustness of the classifier by considering generated examples in rebuilding the classifier. We evaluate our method for the application of static malware detection in portable executable (PE) files. We consider API calls of PE files as their distinguishing features where the feature vector is a binary vector representing the presence-absence of API calls. In our method, we first create a dataset of benign samples by querying the target classifier. We next construct a code table of frequent patterns for the compression of this dataset using the MDL principle. We finally generate an adversarial example corresponding to a malware sample by selecting and adding a pattern from the benign code table to the malware sample. The selected pattern is the one that minimizes the length of the compressed adversarial example given the code table. This modification preserves the functionalities of the original malware sample as all original API calls are kept, and only some new API calls are added. Considering a neural network, we show that the evasion rate is 78.24 percent for adversarial examples compared to 8.16 percent for original malware samples. This shows the effectiveness of our method in generating examples that need to be considered in rebuilding the classifier.
Unsupervised Feature Selection based on Adaptive Similarity Learning and Subspace Clustering
Parsa, Mohsen Ghassemi, Zare, Hadi, Ghatee, Mehdi
Unsupervised Feature Selection based on Adaptive Similarity Learning and Subspace Clustering Mohsen Ghassemi Parsa a, Hadi Zare a,, Mehdi Ghatee b a Faculty of New Sciences and Technologies, University of Tehran, Iran b Department of Computer Science, Amirkabir University of Technology, IranAbstract Feature selection methods have an important role on the readability of data and the reduction of complexity of learning algorithms. In recent years, a variety of efforts are investigated on feature selection problems based on unsupervised viewpoint due to the laborious labeling task on large datasets. In this paper, we propose a novel approach on unsupervised feature selection initiated from the subspace clustering to preserve the similarities by representation learning of low dimensional subspaces among the samples. A self-expressive model is employed to implicitly learn the cluster similarities in an adaptive manner. The proposed method not only maintains the sample similarities through subspace clustering, but it also captures the discriminative information based on a regularized regression model. In line with the convergence analysis of the proposed method, the experimental results on benchmark datasets demonstrate the effectiveness of our approach as compared with the state of the art methods.
Doubly Robust Off-Policy Actor-Critic Algorithms for Reinforcement Learning
Islam, Riashat, Seraj, Raihan, Arnob, Samin Yeasar, Precup, Doina
We study the problem of off-policy critic evaluation in several variants of value-based off-policy actor-critic algorithms. Off-policy actor-critic algorithms require an off-policy critic evaluation step, to estimate the value of the new policy after every policy gradient update. Despite enormous success of off-policy policy gradients on control tasks, existing general methods suffer from high variance and instability, partly because the policy improvement depends on gradient of the estimated value function. In this work, we present a new way of off-policy policy evaluation in actor-critic, based on the doubly robust estimators. We extend the doubly robust estimator from off-policy policy evaluation (OPE) to actor-critic algorithms that consist of a reward estimator performance model. We find that doubly robust estimation of the critic can significantly improve performance in continuous control tasks. Furthermore, in cases where the reward function is stochastic that can lead to high variance, doubly robust critic estimation can improve performance under corrupted, stochastic reward signals, indicating its usefulness for robust and safe reinforcement learning.