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Localized Adversarial Training for Increased Accuracy and Robustness in Image Classification

arXiv.org Machine Learning

Today's state-of-the-art image classifiers fail to correctly classify carefully manipulated adversarial images. In this work, we develop a new, localized adversarial attack that generates adversarial examples by imperceptibly altering the backgrounds of normal images. We first use this attack to highlight the unnecessary sensitivity of neural networks to changes in the background of an image, then use it as part of a new training technique: localized adversarial training. By including locally adversarial images in the training set, we are able to create a classifier that suffers less loss than a non-adversarially trained counterpart model on both natural and adversarial inputs. The evaluation of our localized adversarial training algorithm on MNIST and CIFAR-10 datasets shows decreased accuracy loss on natural images, and increased robustness against adversarial inputs.


Boosting Classifiers with Noisy Inference

arXiv.org Machine Learning

We present a principled framework to address resource allocation for realizing boosting algorithms on substrates with communication or computation noise. Boosting classifiers (e.g., AdaBoost) make a final decision via a weighted vote from the outputs of many base classifiers (weak classifiers). Suppose that the base classifiers' outputs are noisy or communicated over noisy channels; these noisy outputs will degrade the final classification accuracy. We show that this degradation can be effectively reduced by allocating more system resources for more important base classifiers. We formulate resource optimization problems in terms of importance metrics for boosting. Moreover, we show that the optimized noisy boosting classifiers can be more robust than bagging for the noise during inference (test stage). We provide numerical evidence to demonstrate the benefits of our approach.


Reinforcement Learning and Video Games

arXiv.org Machine Learning

As one part of them, Reinforcement Learning has achieved incredible results in game playing. An intelligent agent will be created and trained with reinforcement learning algorithms to fulfill this tasks. In the Future of Go Summit 2017, Alpha Go which is an AI player trained with deep reinforcement learning algorithms won three games against the world best human player in Go. The success of reinforcement learning in this area shock the world and many researches are launched such as driverless cars. Deep learning methods such as convolutional neural network contributes a lot to this because these techniques solves the problem of dealing with high dimension input data and feature extraction. T-rex Runner is a dinosaur game from Google Chrome offline mode. The aim of the player is to escape all obstacles and get higher score until reaching the limitation which is 99999. The moving speed of the obstacles will increase as time goes by which make it difficult to get the highest score. The code of this project can be found in this link which is written in Python.


Better Communication Complexity for Local SGD

arXiv.org Machine Learning

We revisit the local Stochastic Gradient Descent (local SGD) method and prove new convergence rates. We close the gap in the theory by showing that it works under unbounded gradients and extend its convergence to weakly convex functions. Furthermore, by changing the assumptions, we manage to get new bounds that explain in what regimes local SGD is faster that its non-local version. For instance, if the objective is strongly convex, we show that, up to constants, it is sufficient to synchronize $M$ times in total, where $M$ is the number of nodes. This improves upon the known requirement of Stich (2018) of $\sqrt{TM}$ synchronization times in total, where $T$ is the total number of iterations, which helps to explain the empirical success of local SGD.


Gradient Descent with Compressed Iterates

arXiv.org Machine Learning

We propose and analyze a new type of stochastic first order method: gradient descent with compressed iterates (GDCI). GDCI in each iteration first compresses the current iterate using a lossy randomized compression technique, and subsequently takes a gradient step. This method is a distillation of a key ingredient in the current practice of federated learning, where a model needs to be compressed by a mobile device before it is sent back to a server for aggregation. Our analysis provides a step towards closing the gap between the theory and practice of federated learning, and opens the possibility for many extensions.


Prediction of Overall Survival of Brain Tumor Patients

arXiv.org Machine Learning

--Automated brain tumor segmentation plays an important role in the diagnosis and prognosis of the patient. The main focus of this paper is to segment tumor from BRA TS 2018 benchmark dataset and use age, shape and volumetric features to predict overall survival of patients. The random forest classifier achieves overall survival accuracy of 59% on the test dataset and 67% on the dataset with resection status as gross total resection. The proposed approach uses fewer features but achieves better accuracy than state-of- the-art methods. Medical fraternity considers brain tumor amongst the most fatal type of cancer [1]. Brain tumors are divided into two categories based on origin and malignancy. Former is further classified as primary and secondary.


Differentiable Mask Pruning for Neural Networks

arXiv.org Machine Learning

Huawei Noah's Ark Lab Abstract Pruning of neural networks is one of the well-known and promising model simplification techniques. Most neural network models are large and require expensive computations to predict new instances. It is imperative to compress the network to deploy models on low resource devices. Most compression techniques, especially pruning have been focusing on computer vision and convolution neural networks. Existing techniques are complex and require multistage optimization and fine-tuning to recover the state-of-the-art accuracy. We introduce a Differentiable Mask Pruning (DMP), that simplifies the network while training, and can be used to induce sparsity on weight, filter, node or sub-network. Our method achieves competitive results on standard vision and NLP benchmarks, and is easy to integrate within the deep learning toolbox. Introduction Recent models on machine translation, self-driving cars, Alpha Go have shown game-changing breakthroughs.


Byzantine-Resilient Stochastic Gradient Descent for Distributed Learning: A Lipschitz-Inspired Coordinate-wise Median Approach

arXiv.org Machine Learning

-- In this work, we consider the resilience of distributed algorithms based on stochastic gradient descent (SGD) in distributed learning with potentially Byzantine attackers, who could send arbitrary information to the parameter server to disrupt the training process. T oward this end, we propose a new Lipschitz-inspired coordinate-wise median approach (LICM-SGD) to mitigate Byzantine attacks. We show that our LICM-SGD algorithm can resist up to half of the workers being Byzantine attackers, while still converging almost surely to a stationary region in non-convex settings. Also, our LICM-SGD method does not require any information about the number of attackers and the Lipschitz constant, which makes it attractive for practical implementations. Moreover, our LICM-SGD method enjoys the optimal O ( md) computational time-complexity in the sense that the time-complexity is the same as that of the standard SGD under no attacks. We conduct extensive experiments to show that our LICM-SGD algorithm consistently outperforms existing methods in training multi-class logistic regression and convolutional neural networks with MNIST and CIF AR-10 datasets. In our experiments, LICM-SGD also achieves a much faster running time thanks to its low computational time-complexity. Fueled by the rise of machine learning and big data analytics, recent years have witnessed an ever-increasing interest in solving large-scale empirical risk minimization problems (ERM) - a fundamental optimization problem that underpins a wide range of machine learning applications. In the post-Moore's-Law era, however, to sustain the rapidly growing computational power needs for solving large-scale ERM, the only viable solution is to exploit parallelism at and across different spatial scales. Indeed, the recent success of machine learning applications is due in large part to the use of distributed machine learning frameworks (e.g., TensorFlow [1] and others) which exploit the abundance of distributed CPU/GPU resources in large-scale computing clusters.


Skin cancer detection based on deep learning and entropy to detect outlier samples

arXiv.org Machine Learning

We describe our methods to address both tasks of the ISIC 2019 challenge. The goal of this challenge is to provide the diagnostic for skin cancer using images and meta-data. There are nine classes in the dataset, nonetheless, one of them is an outlier and is not present on it. To tackle the challenge, we apply an ensemble of classifiers, which has 13 convolutional neural networks (CNN), we develop two approaches to handle the outlier class and we propose a straightforward method to use the meta-data along with the images. Throughout this report, we detail each methodology and parameters to make it easy to replicate our work. The results obtained are in accordance with the previous challenges and the approaches to detect the outlier class and to address the meta-data seem to be work properly.


Subspace clustering without knowing the number of clusters: A parameter free approach

arXiv.org Machine Learning

Subspace clustering, the task of clustering high dimensional data when the data points come from a union of subspaces is one of the fundamental tasks in unsupervised machine learning. Most of the existing algorithms for this task involves supplying prior information in form of a parameter, like the number of clusters, to the algorithm. In this work, a parameter free method for subspace clustering is proposed, where the data points are clustered on the basis of the difference in statistical distribution of the angles made by the data points within a subspace and those by points belonging to different subspaces. Given an initial coarse clustering, the proposed algorithm merges the clusters until a true clustering is obtained. This, unlike many existing methods, does not involve the use of an unknown parameter or tuning for one through cross validation. Also, a parameter free method for producing a coarse initial clustering is discussed, which makes the whole process of subspace clustering parameter free. The comparison of algorithm performance with the existing state of the art in synthetic and real data sets, shows the significance of the proposed method.