Questions tagged [multidimensional-scaling]

Technique that renders observed or computed (dis)similarities among objects into distances in a low-dimensional space (usually Euclidean). It thus constructs dimensions for the data; the objects can be plotted and conceptualized in those dimensions

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Steps to follow for correspondence analysis when each brand is not shown to every respondent

I want to understand the steps followed for correspondence analysis when each brand is not shown to every respondent. Till now I used to assign a number (proportion) to each brand for each attribute ...
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1answer
587 views

Kernel PCA with an SVD algo

Suppose that I have a great algo for calculating the SVD and I want to do Kernel PCA. It is possible to first apply the Kernel function to my data and then run the SVD algo on the transformed data?
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MDS and PCA eigenvalues and eigenvectors

I understand that Multidimensional scaling (MDS) is same as doing Principal Components analysis (PCA) if Euclidean distance is used, this is known as Metric MDS. But I came across this in a book that "...
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Why does some model-based clustering fail to fit with a large number of dimensions?

I am attempting to cluster data using Mclust. The data is originally from a dissimilarity matrix, transformed via multidimensional scaling in R (MASS::isoMDS). As I ...
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1answer
2k views

Analysing data measured as proportional composition

I have a data set on the proportional composition of marine substrate for different locations which I would like to compare. For example, one replicate transect within a location may be 50% sand, 25% ...
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33 views

Issue of multiple scaling method

I plan to use multiple scaling in R and start with a toy example. There are two matrices. The first contains 10 observations and the second one contains two replicated rows. It appears that the ...
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40 views

How to enhance the performance of naive CMDS?

I'm performing Classical MDS on the distance over columns of binary matrix. The result is like this: The points lies on two lines vertical to each other. I don't think useful information is shown in ...
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3answers
4k views

How to project high dimensional space into a two-dimensional plane?

I have a set of data points in a N-dimensional space. In addition, I also have a centroid in this same N-dimensional space. Are there any approaches that can allow me to project these data points into ...
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1answer
4k views

NMDS and variance explained by vector fitting

I just ran a non metric multidimensional scaling model (nmds) which compared multiple locations based on benthic invertebrate species composition. After running the analysis, I used the vector fitting ...
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2answers
5k views

How to best display crosstab data?

I have a 10x10 matrix composed of two variables with 10 brands each. One variable is the brand purchased, the other is the brand considered. My matrix shows a crosstabulation between the two. I need ...
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135 views

The proper scaling for generating uniformly distributed points in the n-d ball of *non-unit* radius?

The question of generating uniformly distributed points on the surface of n-dimensional unit ball has been already posted here a dozen of times. What I'm interested in is the proper scaling when we ...
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5k views

Interpretation of MDS factor plot

Suppose I run Multidimensional Scaling and I got the resulting plot. Can anybody suggest me how to interpret the plot. Please find one of my result below. Here I've 5 concepts which I run the MDS ...
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1answer
372 views

How to scale new datas when a training set already exists

Here is what I have : A scaled training set, with labels. Segmented images, from which I extract new vectors to classify. My classifier is a KNN which would have obviously been trained using my ...
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1answer
520 views

Individual differences scaling, additional investigations

I am learning individual differences scaling (AKA three-way multidimensional scaling) and I want to know what different ways there are to state that my results are reliable. I had to perform ...
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121 views

Sequential or dynamic multidimensional scaling

I am looking for a way to conduct sequential (dynamic) MDS based on several variables coded for a sequence of stimuli. Could anyone direct me to software for this purpose (especially R packages / code)...
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58 views

Computing and comparing semantic networks generated by grouped individuals

I have 2 groups, each containing 20 individuals. For each individual I have a dissimilarity matrix of a number of judged items. I'd like to evaluate whether there is an overall difference between the ...
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3answers
690 views

Metric and Clustering Method

I need some suggestions regarding what kind of metric and clustering analysis I should use. I read a lot of posts but didn't get any hints about this type of data. I have a 3000*5000 matrix, where ...
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1answer
123 views

Is a Biplot suitable ? Domestic Violence VS Non-Violence data

I have a small data set that consists solely of counts. I have several variables. For example State, for each state (Mexican States), for example, Tamauplipas I have the counts of domestic violence ...
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265 views

Quantifying differences in a discrete distribution across several populations

Suppose you have a discrete random variable, $Y$, with a large number (say, $300$) of discrete (which happen to be nominal) possible outcomes. The mass function, $p(y)=P(Y=y)$, is unknown but a sample ...
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915 views

Big-O Scaling of R's cmdscale()

I'm trying to run R's multidimensional scaling algorithm, cmdscale, on roughly 2,200 variables, i.e. a 2,200x2,200 distance matrix. It's taking forever (about a ...
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4k views

Multidimensional scaling pseudo-code

I am planning to write a program that performs MDS. Any pointers to where I can access the pseudo-code for MDS? Thanks!
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1answer
1k views

Help me understand nMDS algorithm

I have been reading Zuur, Ieno and Smith (2007) Analyzing ecological data, and on page 262, they try to explain how nMDS (non-metric multidimensional scaling) algorithm works. As my background is in ...
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1answer
5k views

Adding labels to points using mds and scatter3d package with R

I have a dataset forwhich i have performed an mds and visualized the results using scatterplot3d library. However i would like to see the names of the points on the 3d plot. How do i accomplish that? ...