Questions tagged [data-analysis]

Data Analysis is the process of evaluating data using analytical and logical reasoning to examine each component of the data provided.

15 questions with no upvoted or accepted answers
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similarity/distance measurement between two ranked sequence

Is there an efficient way to measure similarity/distance between two sequences of ranked numbers/letters. The two sequences are of different length, and only have some elements in common? For example,...
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0answers
117 views

Spatio-temopral wavelet analysis

Am quite new to wavelet analysis and would like some help. I am performing a spatio-temporal analysis of monthly gridded rainfall data. With PCA, I can reduce the dimension of the rainfall data into a ...
2
votes
1answer
123 views

How to extract connected components from persistence diagram?

From the given point cloud (Fig. 1), I use Scipy-TDA to extract persistence diagram (Fig. 2). What I'm interested in is to extract 3 circles. For example, I'd like to know 3 center points and labels ...
2
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0answers
31 views

Identifying the time window at which a meteorological factor influences tree growth the most

This is a problem I am encountering in a research project. I have thought of a naive approach to solve it which relies on many assumptions, is not guaranteed to work, and would be tedious and ...
2
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0answers
58 views

Error in treating non-uniformly spaced data as uniform

In discussing smoothing filters, Numerical Recipes p. 772 says ... irregularly sampled data, where the values $f_i$ are not uniformly spaced ... one can simply pretend that the data points are ...
2
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0answers
1k views

Can post-processing use topoSet and createPatch without screwing up the results?

I would like to use patchAverage to obtain the average pressure on an object that consists of multiple patches (due to different boundary conditions), however ...
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0answers
85 views

Eigenfaces Algorithm

This might be a silly quesntion but recently I've been trying to program the eigenface algorithm using PCA, so I arranged the face vectors vertically in a matrix X such as: X = [x1,x2,x3,...,xn]; In ...
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0answers
25 views

Validating a Markov chain and Bagging to find overall model

let´s say I estimated a Markov chain by splitting my data into traning and test data, and estimating the transition matrix for the traning data yields $$ P= \begin{bmatrix} p11 & p12 &...
1
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0answers
31 views

Use custom defined metric(not matrix) in Javaplex

I'm about to get started trying to use Javaplex for the first time for some application in topological data analysis (TDA) and I want to use a custom defined metric. From looking over the documents, I ...
1
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0answers
42 views

Spectra of the energy flux VS transfer spectra?

In direct numerical simulation of turbulence what is the advantage to look at the spectra of the energy flux rather than the transfer spectra? The transfer spectra corresponds to the triple-velocity ...
0
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0answers
21 views

I need help developing a process to map many individual records (from a database) into larger groups

There are many rows of data in a database table, each of which contains many columns. ID (numeric - 12345, 12378, etc) Name 1 - AAA,BBB,CCC Name 2 - dd, ee, ff Name 3 - Ggg, Hhh, Iii The objective ...
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0answers
46 views

Triplet optimization algorithm producing weird results?

I wrote an algorithm for data analysis using the CERN ROOT framework. It takes in three files of sorted UNIX timestamps from a single year and pairs them up in the closest triplets, where each file ...
0
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1answer
74 views

How to improve the efficiency of periodicity detection for long time based lined and gapped datasets

Our data set has $10^4$ data points, but has a long baseline and many gaps. As the histogram shows, the horizontal-axis is time and most of the time, there are no data. The vertical-axis is data ...
-1
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1answer
27 views

Parameter explained by many distributions

If we had, for example, labeled data, where for each entry (label) we have several data distributions associated to it, how can I get something meaningful from them? Is this a solvable problem? Is ...
-1
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1answer
38 views

Trouble Estimating Motor Parameters with Least Squares in MATLAB

Basically, I'm trying to use Least-Squares to estimate the parameters of a DC motor. My system can be modeled by the following matrix equation: $$\begin{bmatrix}V_{input}(t)\\0\end{bmatrix}=\begin{...