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Questions tagged [one-class]

One-class classification, also known as unary classification, tries to identify objects of a specific class amongst all objects, by learning from a training set containing only the objects of that class. This is different from and more difficult than the traditional classification problem, which tries to distinguish between two or more classes with the training set containing objects from all the classes. PU (positive unlabelled) learning is a special case

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What are the anomalies/fault/outliers detection algorithms

I'm working on a weather application that uses data coming from multiple sensors in real time (the data is time series), i've made an anomalies detection model using One Class Support Vector Machines, ...
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software for one class classification with a Bayesian Network

I'm looking for a software package that would allow to do a one class classification with a Bayesian Network (anomaly detection). I was planning to use bnlearn but so far I'm unable to find out if ...
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Geometrical interpretation for a one class svm

I encountered the following question on a test exam: For an unsupervised dataset $X = \{x_1, \dots, x_n\}$ we would like to solve the optimization problem: $$ min_w ||w||^2$$ subject to $$w^T ...
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Why setting SVDD's C-parameter to $> 1$ does not affect the result?

Why setting $C>1$ does not affect the result (compared to $C=1$) according to: https://www.csie.ntu.edu.tw/~cjlin/libsvmtools/#libsvm_for_svdd_and_finding_the_smallest_sphere_containing_all_data ...
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509 views

Can One-Class SVM be used for outlier detection?

According to my readings (Support Vector Method for Novelty Detection, for instance), One-Class SVM can be used for novelty detection only. The purpose of the $\nu$ parameter is to defined the maximum ...
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Where does “ρ” come from in the primary objective function ?

I'm trying to fully understand the primary objective of one-class SVM function. This function is defined in paragraph 3.2 of Enhancing One-class Support Vector Machines for Unsupervised Anomaly ...
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192 views

Bayesian networks for one-class classification

From the definition of one-class classification in wikipedia: In machine learning, one-class classification, also known as unary classification or class-modelling, tries to identify objects of a ...
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2answers
239 views

Anomaly detection in Text Classification

I have built a text classifier using OneClassSVM. I have the training set which corresponds to only one label i.e("Yes") and I don't have the other("NO") label data. My task is to build a classifier ...
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How to choose a method for binary classifier based on only positive and unlabelled examples?

I need to build a binary classifier with machine learning, as I fail to manually choose a combination of features to achieve minimal fraction of false positives. What is best practice for choosing a ...
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2k views

One class SVM for anomaly detection [closed]

During class the tutor referred us to the article Support vector machine for novelty detection with the following illustration I've read the article but couldn't understand the algorithm. How are ...
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1answer
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Anomaly/Outlier detection based on Windows event security logs (logons) using Machine Learning(in Python) [closed]

I am trying to solve a problem of finding Anomalies/Outliers using event security logs of an individual system. Please find the details below: Problem Statement: Find Anomalies/outliers using event ...
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1answer
609 views

GANS: Using Discriminator for prediction

In the past few years, GANs have been a hot topic and a lot of papers are being published every year regarding GANs. But I always see that either the results of the generator are being shown (sample ...
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1answer
1k views

nu parameter in one-class SVM with linear kernel

I have made a one-class SVM model using the Linear kernel. I trained my model with 100000 positive examples, each one having a vector of 59 dimensions. The examples come from a public dataset, which ...
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291 views

Normalising features for One Class SVM

I have my feature space that is Year Month Day Hour Minute Second Lane Direction Speed Flag A sample vector would look like: ...
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782 views

One Class SVM for Time Series data

I am trying to use an OCSVM for my time series data which looks like this: ...
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1answer
1k views

How does a one-class SVM model work?

I am working on a problem involving outliers detection and I found that it was possible to perform this using one-class SVM. I have been googling it and reading some blogs and papers, but I have a ...
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1answer
560 views

Unsupervised learning methods on unlabeled data?

I'm facing with a challenge of unsupervised classification of unlabeled data. The case is, I have circa 1.2 million vehicle warranty claims, and must develop a classification model to tell whether ...
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1answer
344 views

One-class SVM: “training set vs. origin” logic

first of all, I apologize about asking this question again since a similar one was posted recently; I had to repost it since I still don't understand the answer and I had no other way to interact with ...
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One-class svm with given true positive rate

Is it always possible to find a one-class SVM with given true positive rate (TPR)? I used 1-D grid search with cross-validation to find the width parameter of RBF kernel with .90 TPR. The closest ...
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Why One class SVM seperate from the origin

I don't understand what is the intuition behind the idea of finding a hyperplane that separate the training data from the origin if the feature space. To me it would be more intuitive to create a ...
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1answer
193 views

One Class Classification on high dimensional space

I want to solve OCC(one class classification) on images, the input would be an image, the output is if the image belong to the class, and I extract the image feature from a deep neural work, the ...
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3answers
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one class (positive and unlabeled) classification R package

I have two data sets: one for "good old customers" and a newer one with "new customers". My need is to "predict" which ones of the new customers would be rated as "potentially good customers" using ...
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1answer
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Machine Learning algorithm for a lack of domain data?

When a user searches for an item to purchase on a retail website they can input some features of their desired item to narrow down their search results. This produces a list of items that match their ...
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245 views

How to use Probability (-b1) for one-class classification using LibSVM?

I need some information concerning the LibSVM one-class classification. I use -b1 for two-class classification in SvmTrain and my outputs are prob values and prob labels. I want to use the similar ...
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1answer
351 views

Outlier Detection giving almost all training points as outliers

I am trying to run an outlier detection algorithm using python and I have used OneClassSVM and Isolation Forest on a dataset of about 30 points with 5 outliers. I have trained on the 25 points and ...
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1answer
141 views

Using LibSVM for One-Class-Classification

Why do the same instances, in training and testing, get classified as unknown in LibSVM? I'm using the linear kernel function nu=0.1, gamma=0.1 Here is the instance that is in both the training and ...
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181 views

One Class classification using Kernel Density Estimate

I have a dataset of customers who belong to one-class (say C1). I have another data set of customers (C2) and I need to find out how similar are these to customers in C1. This is what I have tried so ...
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1answer
450 views

One-class KNN for Quality Control

I've come across this paper https://uta-ir.tdl.org/uta-ir/bitstream/handle/10106/1827/Sukchotrat_uta_2502D_10083.pdf?sequence=1&isAllowed=y] where it is described a k-Nearest Neighbors Data ...
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1answer
3k views

Best way to train one-class SVM

Let`s say I have training data which contains 10 classes and have build a classifier using this data. When applying this classifier in real life it may encounter examples not belong to the classes ...
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2answers
4k views

What if I train a classifier with only positive example?

I am interested to know what happens if I have enough positive examples and I train a Classifier with those but no negative examples were provided. Since I am interested to find outliers (anything ...
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What is an appropriate metric to optimize for when comparing different models for one-class classification?

Say I have a set of 100 positive and 1,000 unlabeled points. Among those unlabeled, some are presumably similar enough to the positives that they should belong to the positive class. Yet, if I ...
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1answer
29 views

SVM model never fires

Problem Definition The classification problem in hand is to detect an event that should occur (target=1) within the next forward window of fw days using the current environment state which contains ...
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1answer
508 views

what is the appropriate one-class classifier for sequenced categorical data?

Can someone suggest an algorithm for an outlier detection system? My requirements are: it supposed to be a one class classifier, where on training phase, it only fed 'normal' data however the normal ...
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0answers
62 views

Are there kernel-based one-class sparse kernel-based outlier detection methods, e.g. one-class Relevance Vector Machine?

I have a commercial outlier detection problem in moderate dimension (8-25). We have a limited number of true positive tags and can roughly evaluate performance of various methods. So far, the 1-...
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2answers
7k views

Parameter optimization in one-class SVM of LibSVM

I am new to machine learning and SVMs. I have a general question regarding the optimization of parameters in one-class SVM in libsvm in R. I found similar posts but yet not conclusive answer. Can ...
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4answers
3k views

Metrics for one-class classification

How do you calculate precision and recall in one class classification? In other words in one class classification, we just have TP(True Positive) and FN(False Negative). Which metrics we should use ...
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2answers
389 views

What are the classification models that work on single-class classification problems?

Beside SVM, what are the classification models that can be trained by a dataset of only positive training examples? and which of these models are generally known to perform better in such cases? ...
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1answer
325 views

One-class Classification of multidimensional vectors

I have a m x k User-feature matrix (m >> k) obtained by factorizing an original User-websites matrix (m x n) that has #page views as entries. Additionally, there are users (say r) who have been ...
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1answer
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Why we need single class classification?

I have started learning classification in machine learning. I face two terminologies, one is "single class classification" and a the other is "binary class classification". I am confused about when ...
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1answer
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One class classification with libsvm. Accuracy results in 0%

A quick recap for what I want to do, I want to determine if a text is written by the same author or not. Thus I use one-class classification. In my training set (18 samples), it looks like this (for ...
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2answers
4k views

How to set $\nu$ parameter for one-class SVM?

I am trying to perform one-class SVM for novelty detection, so I use cross-validation to find the best $\nu$ parameter, but I found that usually I got a big parameter $\nu$, resulting in a big false ...
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2answers
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Classifier for only one class

In a simple classification, we have two classes: class-0 and class-1. In some data I only have values for class-1, so none for class-0. Now I am thinking about making a model to model the data for ...