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Sorin Ciolofan commented on SPARK-4038:
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Hello!

Just want to add that k-means clustering is highly influenced by the presence 
of outliers so it may provide false results (false positives or false negatives 
for outlier detection). For this reason it was proposed a modified version 
k-mean-- which computes in parallel clusters and outliers 
(http://pmg.it.usyd.edu.au/outliers.pdf).
But one of the best and very promising is a rapid detection of outliers via 
random sampling 
(http://papers.nips.cc/paper/5127-rapid-distance-based-outlier-detection-via-sampling.pdf)
 for which I was proposing a parallel implementation on Map Reduce in one of 
the papers that should be published soon. It is a distance based method, 
providing also a rank for outlierness. I am wondering if would not be possible 
to have an implementation in Spark of this method.

Regards
Sorin

> Outlier Detection Algorithm for MLlib
> -------------------------------------
>
>                 Key: SPARK-4038
>                 URL: https://issues.apache.org/jira/browse/SPARK-4038
>             Project: Spark
>          Issue Type: New Feature
>          Components: MLlib
>            Reporter: Ashutosh Trivedi
>            Priority: Minor
>
> The aim of this JIRA is to discuss about which parallel outlier detection 
> algorithms can be included in MLlib. 
> The one which I am familiar with is Attribute Value Frequency (AVF). It 
> scales linearly with the number of data points and attributes, and relies on 
> a single data scan. It is not distance based and well suited for categorical 
> data. In original paper  a parallel version is also given, which is not 
> complected to implement.  I am working on the implementation and soon submit 
> the initial code for review.
> Here is the Link for the paper
> http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=4410382
> As pointed out by Xiangrui in discussion 
> http://apache-spark-developers-list.1001551.n3.nabble.com/MLlib-Contributing-Algorithm-for-Outlier-Detection-td8880.html
> There are other algorithms also. Lets discuss about which will be more 
> general and easily paralleled.
>    



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