# Star Strider

Last seen: Today Active since 2012

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Hic sunt dracones! PROFESSIONAL: Physician (M.D.): Diplomate of the American Board of Internal Medicine; M.Sc. Biomedical Engineering: Instrumentation, Signal Processing, Control, System Identification, Parameter Estimation NON-PROFESSIONAL: Amateur Extra Class Amateur Radio Operator; Private Pilot, Airplane Single Engine Land, Instrument Rating Airplane; Gamer NOTE: I do not respond to emails or personal messages, unless they are about my File Exchange contributions. Time Zone: UTC-7 (Standard); UTC-6 (Daylight Savings/Summer)

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How do I calculate the duration between two times?

6 hours ago | 0

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how to fill color in 1/4 th circle
A new function in R2024a is the polarregion function. Try this — figure thetas1 = [0.5 1]*pi; radii1 = [1 2]; polarregi...

1 day ago | 0

How to interpolate values given a starting and end point
Use the rescale function — Vrec = [18.2, 18.1, 18.0, 17.9]; Vrange = [50.6 50.3]; Vres = rescale(Vrec, Vrange(2), Vrange(1...

2 days ago | 0

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How can i make 3D graph with multiple 2D graphs?
If the vectors all have the same sizes, just plot them as a matrix using the surf function. t = linspace(0, 1, 25).'; ...

3 days ago | 2

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How to change the spectrogram magnitude to linear?
I susp[ect that you may actually want to use the pspectrum function with the 'spectrogram' type. To understand the differences ...

4 days ago | 0

Best analysis to show how EEG ranges are similar
I’m not certain what you actually want to do. I would be tempted to use Fourier transforms, specifically stft, and compare th...

4 days ago | 0

How to solve non_linear equation
Solve it symbolically — syms z Eqn = z^3 == log(z)*(482036/0.18525)^5 Z = solve(Eqn) Z = vpa(Z) format longG Zd = doub...

4 days ago | 0

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How to find the intersection of linear regression model and yline
Use the interp1 function for this — T(:,1) = [0 1 2 3 4 5].'; T(:,2) = [0 1 2 3 4 5].'; x = T(:,1); y = T(:,2); p = poly...

4 days ago | 0

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I am getting this warning "Matrix is singular to working precision." and my surf plot is not showing.
You need to do element-wise opeerations in your ‘u’ function, so: u = @(x,y)(-4*pi*exp(-5*pi*pi*0.5).*cos(2*pi*x).*sin(pi*y))....

4 days ago | 1

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Designing Yulewalk Filter for a Bandpass Type
The yulewalk filter will be a FIR filter, whiel the original filter is an IIR filter. A FIR filter generally requires a much hi...

5 days ago | 0

Confidence interval calculation. Cannot compute confidence interval for imaginary values.
The parameters aren’t complex. All the results are real. The problem with your code is that in MATLAB, function arguments an...

5 days ago | 0

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How to correct the recording of a daamaged accelerometer in earthquake analysis
If you have the Signal Ptocessing Toolbox, an alternative approach would be to use the highpass (or bandpass to also eliminiate...

5 days ago | 0

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How to use previous answer in new calculation n times
Perhaps something like this — A=[0.3 -0.2; -0.6 0.8]; B=[-14;2]; x=[1;2]; y = x; for k = 1:10 y = A*y+B; ym(:,k)...

6 days ago | 0

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I have purchased the Signal Processing Toolbox but still get an error when trying to use a function
I am not certain what the problem is. imshow(imread('Screenshot 202....49.59 AM.png')) First, run these from a script or you...

6 days ago | 0

difference between 2 values in a vector
Try this — x = [0.2 0.0 0.0 0.0 0.25 0.0 0.0 0.0 0.3 0.0 0.0 0.4 0.0 0.0 0.0 ...

6 days ago | 0

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result spectrogram from lowpass filter still pass frequency above the treshold
See if: y=lowpass(yori,10,100, 'ImpulseResponse','iir'); improves the result. .

6 days ago | 0

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F1(u,v)=0,F2(u,v)=0 with 4 parameters a,b,c,d, 3 of which (a,c,d) are given
a = 1.5; c = 0.4; d = 0.9; b=0.1:0.1:9; syms u v F1 = @(u,v,b) u*(1 - u) - b*u*v/(c*u + 1); F2 = @(u,v,b) 0.5*b*u*v/(c*u +...

7 days ago | 0

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Unrecognized function or variable 'del'.
That should actually work — tic n = 0; for del=0.0:0.4:pi n=n+1; pe(n)=1.2*sin(del); end toc pe A mnore effi...

7 days ago | 0

How to make sure that the horizontal axes of two figures align?
If the figures are open at the same time, you can use the linkaxes function. If they are not, you can use xlim one one figure a...

7 days ago | 0

csv to fft matlab
You cannot calculate the Fourier transfomors without a corresponding sampling frequency or time vector. Assuming the sampling...

7 days ago | 0

SENSITIVITY ANALYSIS OF A SYSTEM OF AN ODE USING NORMALIZED SENSITIVITY FUNCTION
I am not certain that this does everything you want, however it now has the virtue of running without error — epidemic1 fu...

7 days ago | 0

what kind of plot is useful for comparing two matrices?
I am not certain that there is any built-in functtion for this sort of problem. One approach — M1 = randn(5) M2 = M1 + ran...

8 days ago | 1

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How can I connect the upper endpoint of the red curve to the red dot while keeping the curvature nearly the same?
Here are options using pchip, makima and spline — clear all format long warning off figure set(0,'DefaultAxesFontSize',20...

8 days ago | 0

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error in ode45 - function must return a column vector
It would help to have ‘dirfield’ (whatever it is). The other problem is that with one differential equation, ‘y0’ has to have o...

9 days ago | 0

How to convert displacment data in time series to frequency domain ie (from Amplitude (m) v/s time (s) to Amplitude (m) v/s Frequency (Hz)) using fourier transform
I wrote a utility function to do Fourier transforms. Try this — A1 = readmatrix('ellipse_r3.xlsx') figure plot(A1(:,1),...

11 days ago | 0

How to interpolate data as stairs
You answered your own question — stairs. Note that you can get the (x,y) coordinates as outputs from the stairs function if you...

11 days ago | 0

How to remove noise of low frequency signals
Calculate the fft of the green signal (if you do not already know its spectral qualities), then use it to define the cutoff freq...

12 days ago | 0

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How to detect the specific area from an oscilloscope signal
Perhaps something like this — jpgs = dir('*.jpg'); csvs = dir('*.csv'); for k = 1:numel(jpgs) figure imshow(imre...

12 days ago | 1

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