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Data Science

Questions tagged [dbscan]

DBSCAN means density-based spatial clustering of applications with noise and is a popular density-based cluster analysis algorithm.

28 questions
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1answer
11 views

Clustering based on geolocation pair

I am trying to process a large set of location data where a list of start and end coordinate is given. For example, ...
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0answers
11 views

How to find anomalies/outliers in Panel Data?

I have panel data based on 900000 different entities with 384 time steps and the data is not normally distributed. I am looking for outliers/anomalies, this is unsupervised as I have no examples of ...
0
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1answer
29 views

Preparing dataframe to carry k-means clustering [closed]

Im trying to apply 3 different algorithms of clustering on my dataset. to check which one fits the best. I'm confused how should I convert my dataframe -k-means -DBSCAN -hierarchical clustering ...
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2answers
87 views

KMeans vs. DBSCAN

I am trying to understand some basic clustering techniques. What is the main difference between KMeans and DBSCAN? Can we use both techniques for the same problem?
2
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2answers
146 views

How do we interpret the outputs of DBSCAN clustering?

I am starting to learn DBSCAN for clustering but the interpretation part of it seems to be tricky to understand. ...
2
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0answers
20 views

Measure of variety within list/cluster

I have a dataset of about 53000 points. It has been clustered twice, based on two sets of unrelated attributes. For the first clustering (clustering 1) I used DBScan, and it ended up with about 700 ...
0
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1answer
69 views

How do I right feature selection for DBSCAN?

I want to use DBSCAN to recognize any clusters within all text elements from the DOM tree of any webpage. For example all menu items shall be clustered separatey to all main content or footer elements....
2
votes
2answers
68 views

Clustering 1-d array with constraints?

I have following kind of 1-d array data to cluster with a few constraints: The array has length from 50 to 300, floating, some of them close to 0 and some far away. Goal: divide the array into n ...
2
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1answer
44 views

Is there an oriented clustering algorithm?

I'm looking for a clustering algorithm that will make cluster depending on a orientation. The DBSCAN algorithm cluster points based on a constant radius : https://upload.wikimedia.org/wikipedia/...
2
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0answers
135 views

Clustering events in a sequence.

I've a sequence of recurring events I want to group together into representing different operation activities of the underlying process. 1) These events might potentially have an order in their ...
1
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0answers
313 views

Is my data good for (DBSCAN) clustering?

I have a particular dataset consisting of 50k elements with 40 features each. I want to try to cluster the data as it is, without any dimensionality reduction. The main algorithm I am considering is ...
1
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1answer
381 views

DBSCAN - Space complexity of O(n)?

According to Wikipedia, "the distance matrix of size $\frac{(n^2-n)}{2}$ can be materialized to avoid distance recomputations, but this needs $O(n^2)$ memory, whereas a non-matrix based implementation ...
1
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3answers
535 views

What is slowing down classic DBSCAN algorithm

How to apply CSR Matrix on DBSCAN algorithm in python without using any libraries? Update: Matrix size (8580, 126356) I have given a shot and implemented the algorithm. It runs rather slow. I guess ...
1
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2answers
62 views

Clustering of variants of similar news articles

We have data of several news sites, having quite literally millions of entries. As each news site publishes their own version of the news (also each news site may publish several different version of ...
3
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1answer
2k views

Python clustering and labels

i'm currently experimenting with scikit and the DBSCAN algorithm. And i'm wondering how to combine the data with the labels to write them into a new file. I'd also like to understand how the labels ...
-1
votes
1answer
37 views

How to select the second point where derivative is greater than 1 in r? [closed]

I'm looking for the exact value of epsilon to run the DBSCAN clustering algorithm. Here's the KNN distance plot. This chart ...
0
votes
2answers
42 views

Testing unsupervised clustering

Assume we train a KMeans model using data X. This will give a set of centroids that can be used to cluster data X* using a Nearest Centroid Classifier. If we use a density-based model such as DBSCAN ...
1
vote
1answer
319 views

Scaling DBSCAN clustering - minHash?

Applying density based clustering (DBSCAN) on $50k$ data points and about $2k$-$4k$ features, I achieve the desired results. However, scaling this to $10$ million data points requires a creatively ...
0
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1answer
162 views

Clustering documents - how to evaluate results?

I'm using DBSCAN clustering on a set of documents. The documents' content was converted to TF-IDF matrix, and I'd like to find consistent ways to evaluate the clusters when no added information is ...
1
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3answers
1k views

Can you l2 normalize word2vec vectors for density clustering?

I have a situation where i have to cluster word2vec vectors (200 length dimension vectors on a very large corpus). I decided to use Density based clustering (DBSCAN, HDBSCAN) because my dataset is ...
1
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1answer
2k views

How to use precomputed distance matrix and min_sample for DBSCAN clustering method?

I want to perform DBSCAN on my datapoints, but I don't have access to the data, I just have the pairwise distance of datapoints. Additionally, I have no idea about the number of clusters but I do want ...
-1
votes
2answers
221 views

Which Clustering algorithm to use for unique 4Dimension dataset before feeding to correlation?

Lets give an example X: 1 2 3 4 5 Y: .9 .91 .92 .93 .94 Z: 20 36 999 211 M. 4000 3456 1 0 When I have such dataset, Which clustering algorithm to choose ? Also, ...
0
votes
1answer
156 views

How to Interpret the output of PCA?

I have dataset of 50000 values (rows) and 1000 variables (columns). Since this is high dimensional, I am unable to work with just DBSCAN. So I am trying to use PCA (principle component analysis). ...
1
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0answers
112 views

Clustering with restrictions - Silhouette and C index metrics

I am working on clustering with DBSCAN but with a certain constraint: the points inside a cluster have to be not only near in a Euclidean distance way but also near in a geographic distance way. It is ...
7
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1answer
9k views

Knn distance plot for determining eps of DBSCAN

I would like to use the knn distance plot to be able to figure out which eps value should I choose for the DBSCAN algorithm. Based on this page: The idea is to calculate, the average of the ...
3
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1answer
11k views

How to plot/visualize clusters in scikit-learn (sklearn)?

I have done some clustering and I would like to visualize the results. Here is the function I have written to plot my clusters: ...
4
votes
2answers
556 views

How are clusters from DBSCAN sometimes non-convex?

I've been using clustering in my bag of ML techniques for quite some time now, and I've never found a satisfying answer to this question. In DBSCAN, we define a maximum radius with which to form ...
3
votes
1answer
768 views

Clustering pair-wise distance dataset

I have generated a dataset of pairwise distances as follows: id_1 id_2 dist_12 id_2 id_3 dist_23 I want to cluster this data so as to identify the pattern. I ...