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 Support Vector Machines


Support Vector Machines Tutorial – Stats and Bots

#artificialintelligence

If you have used machine learning to perform classification, you might have heard about Support Vector Machines (SVM). Introduced a little more than 50 years ago, they have evolved over time and have also been adapted to various other problems like regression, outlier analysis, and ranking. SVMs are a favorite tool in the arsenal of many machine learning practitioners. At [24]7, we too use them to solve a variety of problems. In this post, we will try to gain a high-level understanding of how SVMs work.


A Deterministic Nonsmooth Frank Wolfe Algorithm with Coreset Guarantees

arXiv.org Machine Learning

We present a new Frank-Wolfe (FW) type algorithm that is applicable to minimization problems with a nonsmooth convex objective. We provide convergence bounds and show that the scheme yields so-called coreset results for various Machine Learning problems including 1-median, Balanced Development, Sparse PCA, Graph Cuts, and the $\ell_1$-norm-regularized Support Vector Machine (SVM) among others. This means that the algorithm provides approximate solutions to these problems in time complexity bounds that are not dependent on the size of the input problem. Our framework, motivated by a growing body of work on sublinear algorithms for various data analysis problems, is entirely deterministic and makes no use of smoothing or proximal operators. Apart from these theoretical results, we show experimentally that the algorithm is very practical and in some cases also offers significant computational advantages on large problem instances. We provide an open source implementation that can be adapted for other problems that fit the overall structure.


The Mean and Median Criterion for Automatic Kernel Bandwidth Selection for Support Vector Data Description

arXiv.org Machine Learning

Abstract--Support vector data description (SVDD) is a popular technique for detecting anomalies. The SVDD classifier partitions the whole space into an inlier region, which consists of the region near the training data, and an outlier region, which consists of points away from the training data. The computation of the SVDD classifier requires a kernel function, and the Gaussian kernel is a common choice for the kernel function. The Gaussian kernel has a bandwidth parameter, whose value is important for good results. A small bandwidth leads to overfitting, and the resulting SVDD classifier overestimates the number of anomalies. A large bandwidth leads to underfitting, and the classifier fails to detect many anomalies. In this paper we present a new automatic, unsupervised method for selecting the Gaussian kernel bandwidth. The selected value can be computed quickly, and it is competitive with existing bandwidth selection methods. Support vector data description (SVDD) is a machine learning technique that is used for single-class classification and anomaly detection.


Vector Space Model as Cognitive Space for Text Classification

arXiv.org Artificial Intelligence

In this era of digitization, knowing the user's sociolect aspects have become essential features to build the user specific recommendation systems. These sociolect aspects could be found by mining the user's language sharing in the form of text in social media and reviews. This paper describes about the experiment that was performed in PAN Author Profiling 2017 shared task. The objective of the task is to find the sociolect aspects of the users from their tweets. The sociolect aspects considered in this experiment are user's gender and native language information. Here user's tweets written in a different language from their native language are represented as Document - Term Matrix with document frequency as the constraint. Further classification is done using the Support Vector Machine by taking gender and native language as target classes.



DC-Prophet: Predicting Catastrophic Machine Failures in DataCenters

arXiv.org Machine Learning

When will a server fail catastrophically in an industrial datacenter? Is it possible to forecast these failures so preventive actions can be taken to increase the reliability of a datacenter? To answer these questions, we have studied what are probably the largest, publicly available datacenter traces, containing more than 104 million events from 12,500 machines. Among these samples, we observe and categorize three types of machine failures, all of which are catastrophic and may lead to information loss, or even worse, reliability degradation of a datacenter. We further propose a two-stage framework-DC-Prophet-based on One-Class Support Vector Machine and Random Forest. DC-Prophet extracts surprising patterns and accurately predicts the next failure of a machine. Experimental results show that DC-Prophet achieves an AUC of 0.93 in predicting the next machine failure, and a F3-score of 0.88 (out of 1). On average, DC-Prophet outperforms other classical machine learning methods by 39.45% in F3-score.


The Machine Learning Abstracts: Support Vector Machines

@machinelearnbot

Last post, we discussed a type of classification algorithm, Decision Trees. There is another machine learning algorithm which can be used for classification, Support Vector Machines (SVM). Just like any classification algorithm, support vector machines learn to classify or divide any given data point into multiple classes. The key to understanding SVMs is to study how it does that. Each data point when plotted visually, can be represented as a vector from the origin.


Peak Criterion for Choosing Gaussian Kernel Bandwidth in Support Vector Data Description

arXiv.org Machine Learning

Abstract--Support V ector Data Description (SVDD) is a machine-learning technique used for single class classification and outlier detection. SVDD formulation with kernel function provides a flexible boundary around data. The value of kernel function parameters affects the nature of the data boundary. For example, it is observed that with a Gaussian kernel, as the value of kernel bandwidth is lowered, the data boundary changes from spherical to wiggly. The spherical data boundary leads to underfitting, and an extremely wiggly data boundary leads to overfitting. In this paper, we propose an empirical criterion to obtain good values of the Gaussian kernel bandwidth parameter . This criterion provides a smooth boundary that captures the essential geometric features of the data. Support V ector Data Description (SVDD) is a machine learning technique used for single-class classification and outlier detection.


Machine Learning Algorithms: A Concise Technical Overview – Part 1

@machinelearnbot

Whether you are a newcomer to machine learning, a newbie to specific algorithms or concepts, or a seasoned ML vet looking for a once-over of an algorithm you haven't seen or used in a while, these short and to-the-point tutorials may provide the assistance you are looking for. Each of these posts concisely covers a single, specific machine learning concept. Support Vector Machines (SVMs) are a particular classification strategy. SMVs work by transforming the training dataset into a higher dimension, which is then inspected for the optimal separation boundary, or boundaries, between classes. In SVMs, these boundaries are referred to as hyperplanes, which are identified by locating support vectors, or the instances that most essentially define classes, and their margins, which are the lines parallel to the hyperplane defined by the shortest distance between a hyperplane and its support vectors.


Python Programming Tutorials

#artificialintelligence

Welcome to a new section in our Machine Learning Tutorial series: Deep Learning with Neural Networks and TensorFlow. The artificial neural network is a biologically-inspired methodology to conduct machine learning, intended to mimic your brain (a biological neural network). The Artificial Neural Network, which I will now just refer to as a neural network, is not a new concept. The idea has been around since the 1940's, and has had a few ups and downs, most notably when compared against the Support Vector Machine (SVM). For example, the Neural Network was popularized up until the mid 90s when it was shown that the SVM, using a new-to-the-public (the technique itself was thought up long before it was actually put to use) technique, the "Kernel Trick," was capable of working with non-linearly separable datasets.