Login
Password
Sources on this Page

> Headlines by Category

 Home / Science / Mathematics

You are using the plain HTML view, switch to advanced view for a more complete experience.

Re: Overloaded Class Constructors
Zangdaarr" wrote in message <o65kg7$abg$1@newscl01ah.mathworks.com>...
> Loren Shure <loren@mathworks.com> wrote in message
> >
> > Basically you handle these situations in one constructor by checking
> > inputs and branching the code.
> >
> > --
> > Loren
> > http://blogs.mathworks.com/loren
>
> Which is absolutely terrible. I can't believe that in 2016 we still cannot overload constructors & methods.

Absolutely absolutely terrible. 2017a and still cannot overload constructors. Branching the code from a single constructor is such a bad idea.
Standard Deviation filtered signal
Dears,

I am haveing some difficult to find a way to solve the problem of the standard deviation.

I have a signal with noises and some peaks. My goal it was to locate theses peaks , before to do it, i filtered the signal to remove the noises and then I locate the desirable peaks. Untill here it was made it

My issue is that I would like to measure the confiability and the standard deviation of theses peaks found comparing with the signal not filtered

I used the command std, but it does not attend my needs. Does anybody has any suggestion?

since now, I thanks you all.
Standard Deviation - in signal filtered
Dears,

I am haveing some difficult to find a way to solve the problem of the standard deviation.

I have a signal with noises and some peaks. My goal it was to locate theses peaks , before to do it, i filtered the signal to remove the noises and then I locate the desirable peaks. Untill here it was made it

My issue is that I would like to measure the confiability and the standard deviation of theses peaks found comparing with the signal not filtered

I used the command std, but it does not attend my needs. Does anybody has any suggestion?

Since now, I thanks you all.
Estimate multiple linear Regression Coefficients
Hello Community,
i need your help.

I have tried to regress like the following Example.
((((( load carsmall
x1 = Weight;
x2 = Horsepower; % Contains NaN data
y = MPG;
X = [ones(size(x1)) x1 x2 x1.*x2];
b = regress(y,X) )))))))))))))))))))))

I have 5 explanatory variables, so i have changed equation X = [ones(size(x1)) x1 x2 x1.*x2];
to:
 X = [ones(size(x1)) x1 x2 x3 x4 x5];

this was an advise by an other user.
(https://de.mathworks.com/matlabcentral/answers/352044-how-to-use-the-regress-function-for-more-than-2-predictors)

When i enter X = [ones(size(x1)) x1 x2 x3 x4 x5]; there is the following Error: "All input arguments must be tables."

The explanatory and explained variables are imported from Excel. The time series have the same length. (17544 values)

Can someone help me pls?

kind regards

Manuel
Artificial neural networks decode brain activity during performed and imagined movements
Filtering information for search engines, acting as an opponent during a board game or recognizing images: Artificial intelligence has far outpaced human intelligence in certain tasks. Researchers are showing how ideas from computer science could revolutionize brain research. They illustrate how a self-learning algorithm decodes human brain signals that were measured by an electroencephalogram (EEG).
Spoiler alert: Computer simulations provide preview of upcoming eclipse
Scientists have forecast the corona of the sun during the upcoming eclipse. The findings shed light on what the eclipse of the sun might look like Aug. 21 when it will be visible across much of the US, tracing a 70-mile-wide band across 14 states.
Median filter problem
Hello fellow Matlab users,


I try to rebuild the medfilt1 function and there is one problem I can't seem to figure out myself.

First, here is my code:

function [output] = medfilt1_mod(input, order)

output = zeros(length(input),1,'double');

count = 1;

order_half = order/2;

for k = 1:length(input)
    count1 = count-order_half;
    count2 = count+order_half;
    window = zeros(order,1,'double');
    
    if count1 <= 0
        window(-count1+1:order) = input(1:order+count1,1);
    end
    if count2 > length(input)
        x = order -(count2-length(input));
        window(1:x) = input(length(input)-x+1:length(input),1);
    end
    
   if count1 > 0 && count2 <= length(input)
       window(1:order) = input(count1+1:count2,1);
   end
    
    output(count,1) = median(window);
    count = count+1;
end

end

You can test this function with y = rand(1,100) and medfilt1_mod(y).

Now what I don't understand is why there is one value missing at position 92.

The values are all okay, it is just this one that is missing and it consequentely adds one value more at the end at position 100.

Can someone look through my algorithm and point out any problems/errors?

Would really appreciate that.
21 de agosto, el gran eclipse americano
El próximo 21 de agosto se producirá el eclipse total de Sol más esperado de los últimos tiempos: el gran eclipse americano. La banda de totalidad cruzará, en diagonal, de oeste a este EE UU y cerca de 100 millones de personas podrán presenciar el fenómeno en directo.
Stateflow sliding mode controller demo

Will‘s pick this week is Stateflow sliding mode controller demo by Bogumila & Zbigniew Mrozek.

I always enjoy a good controls problem modeled with Simulink and Stateflow. Dr. Mrozek’s submission provides a simulation of a “platform mobile carrying robot with welding equipment.” They model the dynamics of the robot as a linear time-invariant system. You can see it represented by the block labeled as “LTI System” in the Simulink model.

Simulink model

To the right is a block labeled “Stateflow Chart.” This is the controller that supplies an input to the robot. If we open up the details of the chart, we observe that there are two control modes: oscillatory and hyperbolic. Both are proportional controls, but they rely on different gain constants (those variables that start with “k” in the u equation).

Stateflow chart

The submission includes a MATLAB script that defines various parameters used by the simulation. The script then executes the simulation for different initial conditions of the robot and different control modes. Effectively, we study what happens when the robot is given a particular initial velocity and initial displacement from the resting position.

The end result is a rather satisfying figure that displays the position of the robot on the x axis and velocity on the y axis. Each point on a given line corresponds to the position and velocity of the robot at a particular moment in the simulation. The green trajectories are hyperbolic and quickly go unstable. The blue trajectories are oscillatory simulations that swirl down to a stable configuration. The red trajectories are from sliding mode runs, a control strategy that offers “fast response and short settling time.”

controller trajectories

Wonderful though this is, there’s always room for improvement. Here are a few ideas I have that would make the exercise easier for the developer and end-user.

  • While the textbook associated with this submission may have an explanation, the script itself provides little insight into the derivation of the linear time-invariant system. A Live Editor script could be used to document the methodology.
  • Better yet, why jump straight into an LTI system when you have Simscape Multibody? You could model the robot and its platform much more clearly and accurately this way. You could then rely on Simulink Control Design to linearize the plant model about any operating point.
  • The Stateflow chart is somewhat unnecessary in this model. So far as I can tell, the controller remains in one of the two modes for the duration of the sim. A simple Switch block or some modification of the run script could be used instead.
  • Simulink Dashboard blocks would help make the model more interactive for anyone interested in trying different test cases without resorting to the script.
  • And finally, the script itself would be greatly simplified if it leveraged SimulationInput objects.

Let us know what you think here or leave a comment for Bogumila & Zbigniew.

Re: Error in icdevice (PicoScope)
Same problem here. Have you / has anyone solved this issue?
Post Selected Items to:

Showing 10 items of 586

home  •   advertising  •   terms of service  •   privacy  •   about us  •   contact us  •   press release design by Popshop •   © 1999-2017 NewsKnowledge