Bjorn Gustavsson

UIT, the Arctic University of Norway

Last seen: Today | Active since 2001

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esitimate parameter and curve fitting kinetic model
Is your model correct? To my (very much non-biology-expert) eyes the ODE for c(1) seem to reduce to: dcdt(1) = C(1)*k*(1/K - 1)...

en dag ago | 0

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Unexpected behavior of FFT
In the field (IS-radar) I work we have typical carrier-frequencies of 224-1000 MHz and the modulation band-width is a couple of ...

7 dagar ago | 0

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HELP need to run Chebyshev code!
Save your chebeval-function in a separate file chebeval.m. Then call that function from your script. For now you can put both sc...

8 dagar ago | 0

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SIR model with recovered individuals may lose their immunity and become reinfected with the disease. But came with a failure about integration tolerances
You have an error in the SIR-equations. They should look something like this: %% fc_ode_SIR function dq = fc_ode_SIR(~,q,p) % ...

10 dagar ago | 0

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Skipping certain lines using fscanf
For this rather loose file-format specification that you've been given (meaning that in a couple of days, weeks or months it wil...

10 dagar ago | 0

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PLOT surface using 3 vectors of same length (NEED HELP!!!)
You can use multiple indices in the variables you create. For example if you do things like this: b=0; for i = -200:1:200 ...

16 dagar ago | 0

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Gradient Descent Implementation on a function, as opposed to an equation
You could do something like this: 1, rewrite the function to take an array as input-parameter instead of a number of scalar par...

22 dagar ago | 0

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Y-values for the histogram
Perhaps you look for histcounts? Seems like that is the function that returns what is plotted in histogram. HTH

23 dagar ago | 0

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How to fix "matrix dimensions must agree" error
Whe you run into problems like this you will have to learn to use the debug-capabilities of matla. Do this at the command-line: ...

23 dagar ago | 0

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adding counts of ordered pairs
One way to go about this is to use sparse: A1 = [1 4 3; 3 5 1; 12 4 7; 13 5 2; 14 1 1]; A2 = [1 5 ...

23 dagar ago | 0

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Answered
How to use Eigenvector and Eigenvalues of a matrix to formulate Entropy equation?
First you should extract the eigenvalues from the diagonal matrix (mainly for convenience): vLambda = diag(Vect); Then you wan...

24 dagar ago | 0

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Answered
Simultaniously fitting 4 functions: two functions share all parameters, all four functions share one parameter
function errtot = four_errorfcns(pars1to5,Xall,Yall,sigmaYall) err1 = sum( ( f1(pars1to5(1:3),Xall(1,:))-Yall(1,:) ).^2/sigmaYa...

28 dagar ago | 0

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How to create stacked quiver plots?
This sounds like a straight use of quiver3? Either h1=quiver3(slice2(:,1),... slice2(:,2),... slice2(:,...

28 dagar ago | 1

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Plot multiple x axes on the bottom of a graph
You should have some good use of a couple of such tools from the file exchange: dual_axes addaxis multiple-y-axes The last t...

28 dagar ago | 0

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Integration of system of ODEs fails, unable to meet integration tolerances
After only quickly looking at your problem, it seems to me that you launch the body in a direction into Earth. The first 2 and l...

28 dagar ago | 1

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Answered
Unrealistic fitting confidence levels in noisy data
This is most likely due to the large number of data-points you have. Compare with the simpler case of the uncertainty of the ave...

28 dagar ago | 1

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Using geointerp and los2
If you check the documentation (browse on from the help) you will see this: load topo Create a raster reference object assoc...

29 dagar ago | 0

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M_map file with contourf
You might get away by modifying the colormap with the brighten function, perhaps something like: brighten(-0.5) This should ch...

30 dagar ago | 0

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Answered
How to integrate using trapz function
The variable in X1 seems awfully constant, at 0.0166. The first input to trapz should be the x-coordinate of the points at which...

30 dagar ago | 0

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How to convert gray image frame into video frames?
Have a look at the help and documentation for the VideoWriter and writeVideo functions. HTH

ungefär 2 månader ago | 0

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how to attach a matrix generated in loop below a matrix with same row size generated in previous iteration?
The "natural" interpretation of below to me would be something like this: C = [A;B]; But that only works if the number of colu...

ungefär 2 månader ago | 0

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How can i fit ODE parameters to given frequency and amplitude data pairs with "lsqcurvefit"?
There are two issues you will have to solve. The first is to convert your second order ODE to two coupled first-order ODEs. The ...

ungefär 2 månader ago | 0

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Surface plot of scatter data X,Y,Z where unknown data is noise
If you have a good handle on the noise-distribution you could do that. But for plotting purposes I would go for setting missing ...

ungefär 2 månader ago | 1

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Test if input number is divisible by 3.
Have a look at the help and documentation for while. Also from the question I guess that you're reasonably new to programming. I...

ungefär 2 månader ago | 0

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Fast fourier tranformer for Time series data
It seems that you're a bit too close to the Nyquist frequency. If you try: [NUM,TXT,RAW]=xlsread('data.xlsx'); dt = mean(diff(...

ungefär 2 månader ago | 0

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Anisotropic diffusion for a fingerprint image: resolution issues.
You might find that you have more control over the anisotropic diffusion with the cedif or eedif functions from the nonlinear-di...

ungefär 2 månader ago | 1

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Detect and remove outliers in signals
Be very cautious when changing bad-data-values to some default-value - that will eventually lead to (since we all know that the ...

ungefär 2 månader ago | 0

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Histogram or bar graph with greater than bin?
Maybe something like this would be good enough/a step on the way: a = 75*randn(2048,1).^2; h = histogram(min(a,260),0:10:260,'...

ungefär 2 månader ago | 1

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Append to original file name and and save new file to directory?
You should be able to separate the path, name and ext of the full filename using fileparts. That should make it reasonably strai...

ungefär 2 månader ago | 0

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Answered
Linear interpolation using inter1 function in matlab
First you should learn to read the help to the function you struggle with. Do that carefully and you will see that the typical u...

ungefär 2 månader ago | 0