Accuracy
Machine Learning CICY Threefolds
Bull, Kieran, He, Yang-Hui, Jejjala, Vishnu, Mishra, Challenger
The latest techniques from Neural Networks and Support Vector Machines (SVM) are used to investigate geometric properties of Complete Intersection Calabi-Yau (CICY) threefolds, a class of manifolds that facilitate string model building. An advanced neural network classifier and SVM are employed to (1) learn Hodge numbers and report a remarkable improvement over previous efforts, (2) query for favourability, and (3) predict discrete symmetries, a highly imbalanced problem to which the Synthetic Minority Oversampling Technique (SMOTE) is applied to boost performance. In each case study, we employ a genetic algorithm to optimise the hyperparameters of the neural network. We demonstrate that our approach provides quick diagnostic tools capable of shortlisting quasi-realistic string models based on compactification over smooth CICYs and further supports the paradigm that classes of problems in algebraic geometry can be machine learned.
q-Space Novelty Detection with Variational Autoencoders
Vasilev, Aleksei, Golkov, Vladimir, Lipp, Ilona, Sgarlata, Eleonora, Tomassini, Valentina, Jones, Derek K., Cremers, Daniel
In machine learning, novelty detection is the task of identifying novel unseen data. During training, only samples from the normal class are available. Test samples are classified as normal or abnormal by assignment of a novelty score. Here we propose novelty detection methods based on training variational autoencoders (VAEs) on normal data. Since abnormal samples are not used during training, we define novelty metrics based on the (partially complementary) assumptions that the VAE is less capable of reconstructing abnormal samples well; that abnormal samples more strongly violate the VAE regularizer; and that abnormal samples differ from normal samples not only in input-feature space, but also in the VAE latent space and VAE output. These approaches, combined with various possibilities of using (e.g.~sampling) the probabilistic VAE to obtain scalar novelty scores, yield a large family of methods. We apply these methods to magnetic resonance imaging, namely to the detection of diffusion-space (\mbox{q-space}) abnormalities in diffusion MRI scans of multiple sclerosis patients, i.e.~to detect multiple sclerosis lesions without using any lesion labels for training. Many of our methods outperform previously proposed q-space novelty detection methods.
System Can Shut Down Wind Turbines To Save Eagles
A golden eagle is seen flying over a wind turbine wind farm in Wyoming. Maybe not as many as some opponents would have you believe, but it's a problem for the renewable energy industry (along with improper siting in bird flight paths). Of course, coal-fired energy in the United States kills birds too. Eagles, also a symbol of America, hold a special place in the wildlife world. They're protected by federal law, and certainly worth protecting from the whooshing blades of wind turbines.
Machine Learning Stops Web Application Threats while Reducing False Positives
Cybercriminals are increasingly targeting public and internal web applications. Today, nearly half of all data breaches are caused by attacks targeting web application vulnerabilities. To protect your organization from such attacks, Web Application Firewalls (WAFs) are the gold standard. However, some organizations are reluctant to use these devices as they have a reputation for being very resource-intensive, especially when it comes to quickly addressing false positive detections in order to ensure that legitimate users and applications don't get blocked. The primary reason for the high number of false positive detections generated by most WAF solutions is the underlying core behavioral threat detection method being used.
Drones are now being trained to spot violent people in crowds
Get your Minority Report or Skynet references ready, researchers at the University of Cambridge are working on a way to use AI and drone surveillance to spot violent behavior in crowds. The research paper even has a cool sci-fi name: Eye in the Sky. The project uses an inexpensive Parrot AR 2.0 drone to watch crowds of people from above. Then it uses AI to identify people in violent poses (the paper mentions strangling, punching, kicking, shooting and stabbing). It's important to note that the researchers didn't fly a drone around to detect real violence -- The Verge reports it shot its own video clips using volunteers.
Assessing the impact of machine intelligence on human behaviour: an interdisciplinary endeavour
Gรณmez, Emilia, Castillo, Carlos, Charisi, Vicky, Dahl, Verรณnica, Deco, Gustavo, Delipetrev, Blagoj, Dewandre, Nicole, Gonzรกlez-Ballester, Miguel รngel, Gouyon, Fabien, Hernรกndez-Orallo, Josรฉ, Herrera, Perfecto, Jonsson, Anders, Koene, Ansgar, Larson, Martha, de Mรกntaras, Ramรณn Lรณpez, Martens, Bertin, Miron, Marius, Moreno-Bote, Rubรฉn, Oliver, Nuria, Gallardo, Antonio Puertas, Schweitzer, Heike, Sebastian, Nuria, Serra, Xavier, Serrร , Joan, Tolan, Songรผl, Vold, Karina
This document contains the outcome of the first Human behaviour and machine intelligence (HUMAINT) workshop that took place 5-6 March 2018 in Barcelona, Spain. The workshop was organized in the context of a new research programme at the Centre for Advanced Studies, Joint Research Centre of the European Commission, which focuses on studying the potential impact of artificial intelligence on human behaviour. The workshop gathered an interdisciplinary group of experts to establish the state of the art research in the field and a list of future research challenges to be addressed on the topic of human and machine intelligence, algorithm's potential impact on human cognitive capabilities and decision making, and evaluation and regulation needs. The document is made of short position statements and identification of challenges provided by each expert, and incorporates the result of the discussions carried out during the workshop. In the conclusion section, we provide a list of emerging research topics and strategies to be addressed in the near future.
Revisiting the Importance of Individual Units in CNNs via Ablation
Zhou, Bolei, Sun, Yiyou, Bau, David, Torralba, Antonio
We revisit the importance of the individual units in Convolutional Neural Networks (CNNs) for visual recognition. By conducting unit ablation experiments on CNNs trained on large scale image datasets, we demonstrate that, though ablating any individual unit does not hurt overall classification accuracy, it does lead to significant damage on the accuracy of specific classes. This result shows that an individual unit is specialized to encode information relevant to a subset of classes. We compute the correlation between the accuracy drop under unit ablation and various attributes of an individual unit such as class selectivity and weight L1 norm. We confirm that unit attributes such as class selectivity are a poor predictor for impact on overall accuracy as found previously in recent work \cite{morcos2018importance}. However, our results show that class selectivity along with other attributes are good predictors of the importance of one unit to individual classes. We evaluate the impact of random rotation, batch normalization, and dropout to the importance of units to specific classes. Our results show that units with high selectivity play an important role in network classification power at the individual class level. Understanding and interpreting the behavior of these units is necessary and meaningful.
On Adversarial Risk and Training
Suggala, Arun Sai, Prasad, Adarsh, Nagarajan, Vaishnavh, Ravikumar, Pradeep
In this work we formally define the notions of adversarial perturbations, adversarial risk and adversarial training and analyze their properties. Our analysis provides several interesting insights into adversarial risk, adversarial training, and their relation to the classification risk, "traditional" training. We also show that adversarial training can result in models with better classification accuracy and can result in better explainable models than traditional training. Although adversarial training is computationally expensive, our results and insights suggest that one should prefer adversarial training over traditional risk minimization for learning complex models from data.
Feature selection in functional data classification with recursive maxima hunting
Torrecilla, Josรฉ L., Suรกrez, Alberto
Dimensionality reduction is one of the key issues in the design of effective machine learning methods for automatic induction. In this work, we introduce recursive maxima hunting (RMH) for variable selection in classification problems with functional data. In this context, variable selection techniques are especially attractive because they reduce the dimensionality, facilitate the interpretation and can improve the accuracy of the predictive models. The method, which is a recursive extension of maxima hunting (MH), performs variable selection by identifying the maxima of a relevance function, which measures the strength of the correlation of the predictor functional variable with the class label. At each stage, the information associated with the selected variable is removed by subtracting the conditional expectation of the process. The results of an extensive empirical evaluation are used to illustrate that, in the problems investigated, RMH has comparable or higher predictive accuracy than the standard dimensionality reduction techniques, such as PCA and PLS, and state-of-the-art feature selection methods for functional data, such as maxima hunting.
Residual Unfairness in Fair Machine Learning from Prejudiced Data
Recent work in fairness in machine learning has proposed adjusting for fairness by equalizing accuracy metrics across groups and has also studied how datasets affected by historical prejudices may lead to unfair decision policies. We connect these lines of work and study the residual unfairness that arises when a fairness-adjusted predictor is not actually fair on the target population due to systematic censoring of training data by existing biased policies. This scenario is particularly common in the same applications where fairness is a concern. We characterize theoretically the impact of such censoring on standard fairness metrics for binary classifiers and provide criteria for when residual unfairness may or may not appear. We prove that, under certain conditions, fairness-adjusted classifiers will in fact induce residual unfairness that perpetuates the same injustices, against the same groups, that biased the data to begin with, thus showing that even state-of-the-art fair machine learning can have a "bias in, bias out" property. When certain benchmark data is available, we show how sample reweighting can estimate and adjust fairness metrics while accounting for censoring. We use this to study the case of Stop, Question, and Frisk (SQF) and demonstrate that attempting to adjust for fairness perpetuates the same injustices that the policy is infamous for.