# Tagged Questions

18 views

### Clustering using different distance measures [duplicate]

I do unsupervised clustering for a dataset using k-means algorithm. I want to know what is the difference between different distance measures (Euclidean, cityblock, cosine and correlation,...etc). I ...
41 views

### Extract (ultrametric) distances from hclust or dendrogram

How can the matrix of (ultrametric) distances be extracted from the result of hclust (or a dendrogram in general) in R? The ...
72 views

### Computing a distance matrix between multiple multivariate time series

This question has also been asked on stackoverflow.com. Yet my aim is to ask for efficiency gains on the aforementioned platform. My aim here is the correctness of my approach. I am trying to cluster ...
36 views

### How to test the significance of clusters?

How can one test the significance of the clusters obtained after a clustering procedure? Are there separate tests for the distance/similarity/dissimilarity measure used to get the distance matrix and ...
63 views

### Cluster with distance threshold in R

I'd like to get clusters with a maximum inner distance threshold. Now I use hc <- hclust(d) and cutree(hc, numofclasses). ...
35 views

### string clustering: similarity criterion

I have a set of strings of dimension $10,000$. I want to group similar strings together in one group, perform clustering. As string metric, I am using the ...
206 views

### Use of a Poisson distribution from a distance matrix to determine dbscan parameters

I´ve been researching about automatic determination of parameters for DBSCAN (a density-based clustering algorithm -- http://en.wikipedia.org/wiki/DBSCAN), especially eps, and have found the following ...
275 views

### distance measure of angles between two vectors, taking magnitude into account

Suppose I have two vectors, v1 and v2, from which I can calculate the angle between these two vectors as a measure of their ...
768 views

### How to standardize data for hierarchical clustering?

When running hierarchical clustering analysis of a matrix of individuals x samples (e.g., employee performances across different days), there are several ...
42 views

### Creating statistically similar sequences

I have to run a test on a program, with some statistical tools to make sure its results are statistically acceptable. This program will take sequences of data information (a vector of integers or ...
145 views

### What distance method to use in this scenario?

I have a 10 dimensional space which contain points that contain a 1 or 0 . example of two points : point1 : 1,1,1,0,0,0,1,1,0,1 point2 : 1,0,1,0,0,0,1,0,0,0 ...
658 views

### What are distances between variables making a covariance matrix?

I have a $n \times n$ covariance matrix and want to partition variables into $k$ clusters using hierarchical clustering (for example, to sort a covariance matrix). Is there a typical distance ...
296 views

### Finding a known number of circle centers that maximize the number of points within a fixed distance

I have a set of 2-D data where I want to find the centers of a specified number of centers of circles ($N$) that maximize the total number of points within a specified distance ($R$). e.g. I have ...
278 views

### KL divergence or similar “distance” metric between two multivariate distributions

I have a large dataset composed of many samples; each sample is as follows: imagine a grid indexed by i,j for a sample k, I have Y_k, where Y_k(i,j) is the probability density for k at (i,j) of ...
390 views

### What are the use cases related to cluster analysis of different distance metrics?

I'm trying to use different distance metrics like Euclidean, Manhattan, cosine, chebyshev among other distance metrics in my k-means algorithm to calculate distances between the data points and the ...
451 views

### Does Mahalanobis distances have “significance” associated with them?

I have a "distance matrix". let's say a 6x6 distance matrix, each cell is the Mahalanobis distance of two "clusters" (or sets/groups of things in a multidimensional space), I want to "count" the ...
355 views

### Cluster analysis with skewed distibutions

For my master's thesis I would like to use different clustering algorithms to cluster municipalities (as objects) in regard to their land-use characteristics (as variables). Analyzing my data ...
118 views

### Is concept of similarity objective?

Imagine following example: We have two pairs of points (i.e. 4 objects in some space) and two similarity measures. According to first similarity measure, objects from first pair are more similar then ...
370 views

### (hierarchical) cluster analysis with non-standard distance

My question is triggered by a question that was asked on stackoverflow: http://stackoverflow.com/questions/12198115/using-different-metric-for-hclust-linkage. The thing is this: I can formulate an ...
363 views

### Specifying the number of clusters in nearest neighbor clustering

I've got a distance matrix between examples. I want to cluster them into m clusters with a nearest neighbor algorithm which works like this: ...
2k views

### How to perform k-means clustering with only a distance function, not euclidean points?

I want to perform k-means clustering on some objects I have, but the objects aren't described by "points". However, I am able to compute the distance between any two objects (it is based on a ...
878 views

### Distance threshold for clustering

Usually online clustering methods (based on kmeans or not) define a distance threshold value. If a new data-point $x$ is far enough from the nearest center $c$ (i.e. the distance from $x$ to $c$ is ...
2k views

### Using a cosine similarity does not work for any dataset

I have a clustering algorithm, where if I use an euclidian distance as similarity, it works well on any dataset. If I replace it by a cosine similarity (see my code bellow), it will give a degenerate ...
143 views

### Use of autoregressive metric for ARIMA clustering and analysis

I wonder if anyone has put into use the autoregressive metric for ARIMA clustering proposed by Corduas and Piccolo (2008). The authors define the distance autoregressive metric between two processes ...
2k views

### Gower's dissimilarity index

I would like to ask a question about Gower similarity/dissimilarity index. Is it ok to use the Gower dissimilarity measure with Ward linkage clustering? I was reading that the Gower similarity index ...
609 views

### Can I use log-likelihood distance on data of only continuous variables?

I have to run a SPSS two-step cluster analysis. All my 4 variables are continuous scalar standardized parameters (with normal distribution). The dataset includes 10,000 cases. SPSS suggest to use ...