The tag has no wiki summary.

learn more… | top users | synonyms

0
votes
1answer
18 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). ...
1
vote
0answers
33 views

Average minimum distance between two random vectors

Let $\mathbf{y_1} =\begin{bmatrix}g_1x_1 & g_2x_1 & \dots & g_Nx_1 \end{bmatrix}$ and $\mathbf{y_2} = \begin{bmatrix} f_1x_2 & f_2x_2 & \dots & f_Nx_2\end{bmatrix}$. All the ...
2
votes
1answer
54 views

Multidimensional Scaling “eurodist”

I have a question regarding Multidimensional Scaling. I used the dataset eurodist from the package datasets to generate a 2 ...
0
votes
0answers
6 views

Too Large Values with Assembled Distance Transform

I am trying to apply ADT as a distance between two images or their DCT coefficents. The ADT is given as (image taken from "Bidirectional PCA with assembled matrix distance metric for image recognition ...
0
votes
0answers
32 views

How genetic beta-diversity reflects traditional beta-diversity?

Im trying to figure out how betadisper {vegan, R}, and more specifically how the 'average distance to median' relates to betadiversity in a more traditional sense. betadisper calculates the variance ...
0
votes
0answers
24 views

Normalized cross correlation vs Euclidean distance in template matching

What is the difference between normalized cross-correlation and Euclidean distance in pattern recognition? -- especially if we want to do recognition with template matching. I understand about ...
0
votes
1answer
15 views

Distance Transform In Image?

I understand how to compute Distance Transform for BW image In BW image we can calculate the distance of the pixel with non zero pixel value using Eucledian Distance. But I dont undertand how to ...
0
votes
1answer
20 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 ...
3
votes
1answer
83 views

Is there an intuitive characterization of distance correlation?

I've been staring at the wikipedia page for distance correlation where it seems to be characterized by how it can be calculated. While I could do the calculations I struggle to get what distance ...
2
votes
1answer
96 views

Confidence interval for distance from center

We have a bivariate normal process where $X \sim N(\mu_x, \sigma), \, Y \sim N(\mu_y, \sigma)$, with no covariance. $(\mu_x, \mu_y)$ are unknown. (For convenience we can assert that $\sigma = 1$, or ...
0
votes
0answers
38 views

Learning from distance matrices

I have a task to build multi-task classification model based on distance (similarity) matrix only. They are already precalculated and no changes here can be applied. Can you, please, recommend me ...
1
vote
0answers
30 views

Why it is better to use the cumulative distribution to compute distances?

In the comments of this question, it was pointed out that, when comparing two distributions, it is more natural and more general use the cumulative distribution (CDF) instead of the distribution ...
0
votes
0answers
33 views

Distance between nominal vectors: a review

I have a seemingly easy question which however is troubling me a bit. I have couples of vectors made up of nominal attributes. They can be of different length and sometimes some of the attributes in ...
1
vote
0answers
23 views

Computing a “concentration of event occurrence” index

I'm looking at the concentration of an event occurrences in a given interval of time. For example, we suppose that an event occurred 4 times in an interval of length 10. I can represent this as a ...
2
votes
0answers
62 views

Genetic distance over spatial scales

I have matrices of genetic distances for x number of individuals within a population and their corresponding point coordinates -one genetic distance matrix per point coordinates. I was imagining ...
1
vote
1answer
44 views

Jensen-Shannon divergence for finite samples

I have two finite samples $s_1$ and $s_2$ and two distributions $p_1(s_1)$ and $p_2(s_2)$ that are associated to these samples. I'm essentially interested to measure the distance or similarity between ...
0
votes
0answers
20 views

Distance from bivariate Gaussian mean in terms of variance

Not sure if my question is a valid one but I will just put it out here. Consider a bivariate data set $(x_i, y_i)$ $[i=1,...,n]$ to which a bivariate Gaussian Distribution is fitted. Now, consider ...
0
votes
0answers
29 views

Earth Mover's Distance (EMD) between two Gaussians

Is there a close formula (or some kind of bound) on the EMD between $x_1\sim N(\mu_1, \Sigma_1)$ and $x_2 \sim N(\mu_2, \Sigma_2)$?
1
vote
0answers
76 views

Summing up two matrices of distances among centroids

I am ecologist, using mainly the 'vegan' R package. I want to combine ('cbind') 2 matrices (sample x species) but samples (row) are different. I sampled within 24 sites, by using 2 distinct methods, ...
0
votes
0answers
48 views

Finding the best path through the matrix in DTW

I have two time series q and c and I want to calculate dynamic time wrapping (DTW) distance between these two time series: ...
3
votes
1answer
60 views

Multi-variate normal distribution distance from vector sub-space

let X $\sim {\cal N}(\mu,C)$ be a random variable obeying multi-variate normal distribution in $\mathbb{R}^n$ and $U \subset \mathbb{R}^n$ be a vector space with $\dim(U)=n-1$. What is the probability ...
1
vote
1answer
79 views

Cook's distance and $R^2$

I am currently running a linear regression and calculating its $R^2$ After that. I calculate the Cook's distance of all points and throw away from the analysis all of the points with a distance ...
1
vote
1answer
62 views

Support Vector Machine for Longitude-Latitude data

I am wondering if someone could point me to the direction of support vector machines being used for longitude latitude. It seems logical that the possible complexity in SVM would be great for ...
1
vote
2answers
417 views

Which distance to use? e.g., manhattan, euclidean, Bray-Curtis, etc

I am not community ecologists but working these days on community ecology data. What I couldnt understand, apart from the mathematics of these distances, is the criteria to which distance to be used ...
0
votes
1answer
111 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 ...
1
vote
1answer
38 views

How to make similarity matrix from two distributions?

My domain expertise is not in statistics, therefore my question might sound stupid to you. I have two different distributions, first has studentIDs as columns and features in row. First Distribution ...
0
votes
0answers
7 views

Population specific attributes to pairwise distances: How to choose a distance?

I've collected a lot of data for different populations and I need to convert them into a pairwise distance measure. There are several distances such as , Bray-Curtis and Manhattan distances. My ...
0
votes
2answers
45 views

Negative values distance model between 2 sets

I have two sets, $A$ and $B$, containing string values. I am trying to model the relationship between sets $A$ and $B$ by computing the following distance: $d = \frac{ \mid A \mid + \mid B \mid- \mid ...
0
votes
0answers
77 views

Is there a term that refers to the distance of an object from the mean?

I am trying to rephrase this sentence: I will compare the difference between the deviation of the student's midterm exam mark in this class from the class average with the deviation of the marks ...
2
votes
1answer
57 views

Distance weighted probability

I would like to know if what I want to calulate has probability of presence/absence is valid or not, and the best way to do it. I have a collection of points, and each point has 5 neighbors. For ...
1
vote
0answers
221 views

Vector space model: cosine similarity vs euclidean distance

I have corpora of classified text. From these I create vectors. Each vector corresponds to one document. Vector components are word weights in this document computed as TFIDF values. Next I build a ...
0
votes
0answers
45 views

Transforming distance matrix to univariate data

Is there a valid mathematical or statistical approach to converting site by site distance objects/matrices to a univariate site vector or column in a dataframe? I have a Euclidean distance matrix for ...
1
vote
2answers
85 views

What is the point of measuring statistical distance?

On pg. 378 of "Cryptography with Tamperable and Leaky Memory", Kalai et al. claim two probability distributions are $e(k)$ close if the distance between them is at most $e(k)$. What is significance ...
0
votes
0answers
48 views

Statistical distance tests

I am using around 200 variables to compare 2 populations, group A and group B. Here's a representation of what the data looks like ...
0
votes
1answer
154 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 ...
1
vote
1answer
102 views

How is “Orthogonal distance” computed?

I was reading the vignette of the R package chemometrics (link). In the second paragraph (right below the first equation) of Page 12, the author writes: the OD ...
0
votes
0answers
89 views

Computing Jensen-Shannon Divergence between discrete and continuous distribution

Is it possible to compute the Jensen-Shannon divergence between a discrete and a continuous probability distribution, e.g. between a standard normal distribution and a distribution taking the values ...
3
votes
2answers
125 views

Choice of distance metric when data is combination text/numeric/categorical

I have a large table of attributes of different real-world movie theaters. I have classified them by the "true" physical entity to which they belong, so that there may be multiple records for a given ...
4
votes
0answers
102 views

Distribution of the hyperbolic distance between random points in the Poincaré disc

Let two points at polar coordinates $(r_i, \theta_i)$ and $(r_j, \theta_j)$ be hyperbolic points in $\mathbb{H}^2_\zeta$ with curvature $K=-\zeta^2$. The radial coordinates of these points are ...
1
vote
2answers
422 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 ...
1
vote
0answers
56 views

Bhattacharyya distance for three histograms

There is a paper “Auto White Balance Based on the Similarity of Chromaticity Histograms” mention about automatic white balance. One of the key point of this algorithm is how to measure the similarity ...
7
votes
7answers
865 views

Pairwise Mahalanobis distance

I need to calculate the sample Mahalanobis distance in R between every pair of observations in a n x p matrix of covariates. I need a solution that is efficient, i.e. only n(n-1)/2 distances are ...
3
votes
2answers
82 views

Similarity theory: Testing whether dimensions are separable or integral

Note: I'm not referring to linear separability. I've found the interesting comment in Edelman, Shahbazi: "Renewing the respect for similarity" that for integral dimensions, Euclidean distance is ...
1
vote
1answer
106 views

Distance between the product of marginal distributions and the joint distribution

Given a joint distribution $P(A,B,C)$, we can compute various marginal distributions. Now suppose: \begin{align} P1(A,B,C) &= P(A) P(B) P(C) \\ P2(A,B,C) &= P(A,B) P(C) \\ P3(A,B,C) &= ...
2
votes
0answers
41 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 ...
4
votes
2answers
126 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 ...
0
votes
0answers
22 views

Using a linear model to update straight line distance to realistic distance (classification)

I have the following situation: users (in total 600 at this point) who should only be matched when the distance between a pair of users is lower than what they allow. I use R's ...
1
vote
1answer
206 views

The derivation of the Mahalanobis distance formula [closed]

I recently asked about the Mahalanobis distance and I got pretty good answers in this post: Bottom to top explanation of the Mahanalobis distance? I think I got the idea, but what I still felt ...
3
votes
2answers
394 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 ...
21
votes
5answers
5k views

Bottom to top explanation of the Mahalanobis distance?

I'm studying pattern recognition and statistics and almost every book I open on the subject I bump into the concept of Mahalanobis distance. The books give sort of intuitive explanations, but still ...