# Questions tagged [spectral-analysis]

For questions involving spectral clustering algorithms, frequency domain analysis or correlated subjects. May include Fourier transform and graph theoretic questions.

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### Regressing Singular Spectral Analysis Eigenvectors on data

I'm trying to model some time series economic data using mostly regression with other independent variables following the Error Correction Model (or Engle Granger approach). The ultimate goal is to ...
15 views

### Interpreting results from preforming Power spectral analysis on Hourly Temperature data

I'm analyzing hourly temperature data for a school project. Analysis data set 1 | Hourly data from 01/01/2020-12/31/2020. So I have n=24*365 = 8760 data points. I did the analysis using R. Let x be ...
1 vote
13 views

### Obtaining frequency content of time sequence

I have a long sequence of time values (instants in time where events happened) and I would like to detect perodicities in this data. It's possible to sample these points onto a gigantic grid and take ...
63 views

### Generating a surrogate time series from unevenly spaced time series

I work in the atmospheric sciences and I have data from an automated weather station measuring mean sea level pressure. Due to an extreme event(and consequent loss of electricity)the measurement is ...
22 views

### Building up to the periodogram

I have seen in multiple sources that if we start with writing a time series as follows (assuming $n$ is odd): $$x_t = a_o + \sum_{j=1}^{(n-1)/2}{[a_jcos(2\pi tj/n) + b_jsin(2\pi tj/n)]}$$ Then we will ...
1 vote
25 views

### Discover a pattern in a set of spectrograms given a real rating

I'm trying to find patterns in a sorted set of spectrograms, each with a rating. The main idea is to train the CNN in such a way that it understands how the pattern "evolves" at each step, ...
40 views

1 vote
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### Estimating Fourier spectrum from multiple time series of a system

I have a set of N time series, each of length T, that describe separate realisations of a single physical system. For each series, I can compute an FFT to find the Fourier spectrum up to a period 2/T, ...
40 views

### HC Covariance Matrix Estimators

I'm looking for assistance in understanding/implementating the following paper Covariance Matrix Estimation in Time Series Where I need help is Eq 33 Assume $EX_i = 0$. Using the idea of lag window ...
125 views

### Interpretation of pooling in Graph Neural Networks

The paper Hierarchical Graph Pooling with Structure Learning (2019) introduces a distance measure between: a graph's node-representation matrix $\text{H}$, and an approximation of this constructed ...
1 vote
416 views

### Periodogram explained

If I plot a periodogram of let's say sin(20x) + 2sin(80x) and it looks like this: What does it say, i.e., how do I interpret this periodogram? How could I compute ...