The data-analysis tag has no wiki summary.
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0answers
72 views
An exact fraction of a matrix
Let $A$ be a $n \times m$ real matrix with $n<<m$ and of rank $r<n$. It is known that $A$ has exactly two distinct non-zero singular values: $\sigma_{\max}$ and $\sigma_{2}$, and also that ...
-3
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1answer
183 views
Hilbert space vector representation for data in a metric space. Where am i wrong in this experiment?
Consider the function space $M$ such that all its elements are of bounded variation, square integrable and of unit norm. An equivalence class is defined over this set as, $f \sim g$ iff for some ...
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0answers
25 views
Coordinates Poisson Cluster parent point
Is there any method to know the position of parent point in 'Poisson Cluster Process'?
For information I use data with poisson distribution. data consist of (longitude, latitude, date).
I want ...
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0answers
94 views
Database of non-isomorphic trees
As there are several free prime number databases, is there something similar for non-isomorphic trees?
4
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0answers
250 views
Implications of a recent result on Benford's law
I want to the discuss the implications of a theorem by J. Morrow (2010) regarding Benford's law.
There are many papers written about Benford's law with a comprenhensive discussion of the advantages ...
18
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5answers
2k views
Inference using Topological Data Analysis: Is it worth it for a regular statistician to learn TDA?
After having read Gunnar Carlsson's http://www.ams.org/journals/bull/2009-46-02/S0273-0979-09-01249-X/S0273-0979-09-01249-X.pdf I feel enthusiastic to use some topological data analysis (TDA) methods ...
8
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2answers
784 views
Easier reference for material like Diaconis's “Group representations in probability and statistics”
I'm teaching a class on the representation theory of finite groups at the advanced undergrad level. One of the things I'd like to talk about, or possibly have a student do any independent project on ...
1
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2answers
295 views
Appropriate histogram comparison distance measure
I am working with hyperspectral image data in R, so I have subset an image to a region of 5000 pixels, each containing a vector 254 bands in length.
I would like to cluster this data in order to try ...
2
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1answer
414 views
correlation for three variables? [closed]
suppose we have three variables here, x,y, z
now, what we know is that the correlation between x and z is 0.6, the correlation between y and z is 0.65.
Here is the question, is there any formula to ...
0
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0answers
96 views
Unusual function computation in signal processing
Hi,
I wonder if there is 'an operation' that allow me to compute this special function faster than square-time $O(n^2)$.
Assume we have functions $f(x)$ and $h(x)$. $h(x)$ has a special point ...
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2answers
420 views
Interpolating a “manifold” between two points
Edit: I have reworded the question.
This may be a basic question but I am having trouble figuring out the correct answer. I want to find a local coordinate chart that fits a d-dimensional ...
9
votes
3answers
1k views
Higher categories as data structures
Still wading through higher category theory. I find the subject a bit intimidating, not so much for technical reasons, but because I lack sufficient intuition as to the motivation(s)/heuristics one ...
0
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0answers
92 views
Extrapolate trend in gridded data
I'm interested in extrapolating measured horizontal wind data of a vehicle into a forecast horizontal wind grid. Given the flight path you have a series of points that are "more accurate" than the ...
2
votes
0answers
108 views
isomap and self intersections
I sample a 2D surface in $\mathbb{R}^3$ with $N$ points, and compute an isomap using pairwise weighted geodesic distances. I am thus able to embed this surface into a $M$ dimensional space in which ...
5
votes
2answers
894 views
Solving for Moore Penrose pseudo inverse
I have a system to solve, set up as :
$$Ax = b$$
with a square rank deficient matrix $A$. The paper suggests to use a Moore Penrose pseudo inverse, which in my case can be computed using the ...
2
votes
1answer
557 views
name for $\underset{x}{\operatorname{argmin}} \displaystyle\sum\limits_{i=1}^n |x_i - x|$
Given a real-valued data set $ x_1, \dots, x_n $, what do you call the quantity
$$\underset{x}{\operatorname{argmin}} \displaystyle\sum\limits_{i=1}^n |x_i - x|$$
This seems like a pretty basic ...
2
votes
0answers
519 views
Classical Multidimensional Scaling
Hi,
I am doing an MDS with a distance matrix coming from geodesic distances between points X on a 3d mesh (ie., not euclidean distances), and try to find points Y in euclidean space which best ...
3
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2answers
21k views
Correlation between 3 variables
For correlation measurement betweeen 2 variables, I use Pearson formula.
What formula can use to find degree of correlation between 3 variables ? My variabes are not symmetric: The correlation in ...
1
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2answers
237 views
Clustering sets of sparse vectors with high dimensionality
I'm trying to write a simple recommendation system. I have a set of products that exist in a set of categories and I know whether a given customer liked a subset of the items. From this I can deduce ...
1
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0answers
403 views
Cluster-preserving and distance-maximizing embedding into Hamming Space?
I have a set of data, each instance in the real $[0,1]^{d}$. However, it's actually all in a relatively small range around 0.5, clustered into classes in even smaller ranges. The actual origin of the ...
