Questions tagged [localoutlierfactor]

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Detection outliers in financial time series taking into account related time series

I would like seek advice on how to build an efficient approach to identify outliers in a financial series taking into account also related series. For example, let's assume the there is a very ...
user3548751's user avatar
4 votes
1 answer

Anomaly detection, LOF vs IsolationForest

I have a training dataset with 140 000 instances with 140 features. Due to the scale of the dataset I'm experiment with letting a model do the anomaly detection and have tried LocalOutlierFactor and ...
Henri's user avatar
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LOF vs k-NN in data with varying density

When the dataset is comprised of regions of varying densities, which technique is more effective for outlier detection Localised Outlier Factor(LoF) or K-Nearest neighbors (KNN)
Surya Tej's user avatar
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1 vote
2 answers

AUC measure for Local outlier detection in python?

I'm using Local outlier factor algorithm provided by Scikit-learn for outlier detection. For the evaluation i want to use auc measure. ...
Imen F's user avatar
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Why is One Class SVM predicting that half my dataset consists of outliers?

I am currently working on a dataset with 14 continuous features, a categorical target over five classes, and 90,000 samples. My current goal is to explore outliers in the dataset, and to that end I ...
Tarek Allam's user avatar
1 vote
1 answer

Anomaly detection on high dimensional Data using k means/SVM/LOF? [closed]

I am working on one Anomaly detection problem (unsupervise problem) Data set have 1) 15 columns and around 8k rows , including normal and abnormal(outlier ) rows, without label , all are numeric ...
user3219871's user avatar
2 votes
2 answers

When forecasting, is it better to remove the outliers or just to transform them?

I am forecasting the number of logins. I have a dataset with the number of logins for each hour. First, I use LOF (local outlier factor) to find the outliers and then I remove them. Second, I use ...
Aizzaac's user avatar
  • 1,179
2 votes
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Should you normalize your training data for Local Outlier Factor

Say I'm using scikits implementation of Local Outlier Factor with euclidean distance being used by the reachability function. My input features are magnitudes apart, so is it advisable that I ...
fill123's user avatar
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2 votes
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LOF (Local Outlier Factor) choosing the value of k

Just want to understand one thing. Let's say for any data set I select k=20 and generate LOF for each point and then I show all the points in the descending order of its LOF. Now when I am analyzing ...
Swapnil Bhure's user avatar
3 votes
0 answers

Difference between identifying outliers using LOF and K-means clustering

I am identifying outliers using K-means and LOF (Local Outlier Factor). Let's say if we are identifying possible outliers using both the techniques, I believe LOF will pick global outliers also as ...
Arpit Sisodia's user avatar