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Star Strider


Last seen: Today
14.171 total contributions since 2012

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.

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Answered
Calculate the date difference
The vectors must have the same sizes. Use between: DaysDiff = between(StartDate(1:numel(EndDate)),EndDate) to get: DaysD...

alrededor de 4 horas ago | 1

| accepted

Answered
How to use ezplot
The ezsurf (and fsurf) functions accept only single-variable functions. Try this: figure ezcontour(@(x,y) x^2 - 9*y^2 - 81...

alrededor de 12 horas ago | 0

Answered
How can I find the successive fluctuations of the ECG data.
See: Identifying QRS point in ECG signal among several others.

alrededor de 23 horas ago | 0

Answered
MATLAB Equivalent of Linregress in Python?
If you have the Statisitcs and Machine Learning Toolbox, there are several options, among which are regress and fitlm. There ma...

1 día ago | 0

Answered
Interpolate, fit, and space data
I have no idea exactly what you want to do, or what your data actually are. For the ‘x’ data, I would probably use the linspa...

1 día ago | 0

Answered
Shading an area between two intervals on a plot
It is likely not possible to use area for this, since that is not how it was designed to be used. It is possible to use patch...

1 día ago | 0

| accepted

Answered
Solution of natural frequency equation with fzero function
The fzero function is likelly not appropriate here. I would instead use fsolve, and convert the obsolete inline call to an anon...

2 días ago | 0

Answered
a problem with power spectrum calculation (FFT)
The mean of ‘data’ is -16657.4418730469. This is the D-C component, so it appears at 0 Hz, and completely prevents the details ...

2 días ago | 0

| accepted

Answered
Comapring Values in one Matrix to another
Another approach: A = [373 383 393 403 413 420 451 485 499]; B = [373 453 457 461 464]; C = ones(numel(B),1)*A; ...

2 días ago | 0

Answered
How to mark the maximum points in mesh
Add this loop just before the mesh call: for k = 1:size(Response_amp,1) [Ramax(k),Idx(k)] = max(Response_amp(k,:)); ...

2 días ago | 0

Answered
plot curve in matlab
syms qa h = (611375/279 - ((192500000*cos(qa))/93 + ((60000*cos(qa))/31 - 611375/93)^2/9 - 14656250/31)/(2*((153125000000*cos(...

2 días ago | 0

Answered
I need to find the angle from horizontal that tangents to a curve make for multiple points
I am not certain what you want to do, or the result you want. The easiest way to calculate numerical derivatives is to use th...

3 días ago | 1

| accepted

Answered
Interpolation to find harmonics from fft
Consider increasing the frequency resolution by using a longer fft. That may make it easier to detect the harmonics where you e...

3 días ago | 0

Answered
Reading Files and plotting in matlab
I am not certain what the responses to the input calls should be, so I did not run your code, only looked at it. It appears ...

3 días ago | 0

| accepted

Answered
system of nonlinear equation
That is not going to woork with fsolve for a number of reasons. It is necessary to convert ‘f’ to a numeric (not symbolic) fu...

3 días ago | 0

Answered
Variables under the same name in different .mat files
Use load to load each of the files into a different structure. See Load List of Variables into Structure Array. You can then...

3 días ago | 0

Answered
Looking for documentation explaining M.' and other symbols to select data from an array
‘M. means the same as M(:,:)‘ No, not ‘M.’. The extra dot will throw an error. I am not certain what you are asking. S...

3 días ago | 0

Answered
Creating a vector of datetimes with increments of 15 minutes
Try this: Timestamp = (datetime('2020-06-30 23:45:00') : -minutes(15) : datetime('2015-01-01 00:00:00')).'; Timestamp.Format ...

4 días ago | 0

| accepted

Answered
simple question of creating a time vector
Without the exact details of your file (that I suspect is not exactly 60 seconds long), something like this will work: t = lin...

4 días ago | 0

| accepted

Answered
different sound file times
If you want all of the sound files to have the same sampling frequency, use the Signal Processing Toolbox resample function. On...

4 días ago | 0

Answered
There is something wrong in R.
The problem is in the way you call the exp function. This works: R = ((2.*h).*(f.^3))./((c.^2).*(exp(h.*f/(k.*T))-1)); .

4 días ago | 1

| accepted

Answered
Plot AREA limit in matlab
If you want the area between ‘abb_per’ and 100 filled, use the patch function. Try this: figure patch([n fliplr(n)],[abb_p...

4 días ago | 0

| accepted

Answered
lowpass() not working
A low passband with a very high sampling frequency is asking a lot of any filter. I am somewhat surprised that lowpass used a F...

4 días ago | 0

Answered
How to plot 3D surface with vector-input function?
The function you coded: FUN = @(x) = x(1).^2+x(2).^2; will only take the first 2 elements of ‘x’ (whatever it is), and will r...

5 días ago | 0

| accepted

Answered
piecewise for use in anonymous functions
One option: Rt0 = @(theta,theta1,theta2,B,H,L1) ((0<=theta) & (theta<theta1)).*(B./2+L1)./cos(theta) + ((theta1<=theta) & (the...

5 días ago | 1

Answered
extract mth and m+1st largest element from a vector
‘Is using sort is the best way?’ Yes.

5 días ago | 0

Answered
How to write a multi line string?
Since ‘tran_models’ is an array, just use a loop: for k = 1:size(tran_models,1) fprintf(File,'%s\n', tran_models(k,:)); ...

5 días ago | 0

| accepted

Answered
How can I plot and reach to this figure ?
birthday = datenum(year, month, day); t = 0:ceil(datenum(now)-birthday); Physical = sin(2*pi*t/23); The rest would be calcula...

5 días ago | 0

Answered
Solving the Kinetic equations by Matlab coding
Try this: % % % k(1) = R_Inf, k(2) = k R1fcn = @(k,t) k(1).*(1-exp(-k(2).*t)); R2fcn = @(k,t) k(1).*(1 - (1-exp(-k(2).*t))...

5 días ago | 0

Answered
Changing scientific notation to long format
Select an appropriate option (such as long g) with the format function.

5 días ago | 0

| accepted

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