rambling -trembling

[Ivan Ramirez]

Hy, anyone has matlab codes of rambling -trembling for an investigation for university?? thank you very much.best regards

[Marcos Duarte]

Re: rambling -trembling

Here is a matlab code for the estimation of the rambling-trembling trajectories.
This code is 15 years old and you may have to change it according to your matlab version.

I hope it helps

Marcos Duarte


function varargout = iep(varargin)
%IEP processes the stabilogram decomposition according to IEP ideas
% (Zatsiorsky & Duarte, 1999).
% [IND,RAMBLING,TREMBLING,NIEP,T0,IEP0]=IEP(T,F,COP)
% Inputs:
% T: time time series [s]
% F: horizontal force time series [N]
% COP: center of pressure time series [mm]
% Outputs:
% IND: initial and final index in relation to the former T
% for RAMBLING and TREMBLING time series
% RAMBLING: rambling time series [mm]
% TREMBLING: trembling time series [mm]
% NIEP: number of IEP
% T0: instants of IEP (by interpolation)
% IEP0: IEP (by interpolation)
% you should avoid use this code with unfiltered data
%Marcos Duarte 5jul98


if nargin ==3
f=varargin{2};
if length(varargin{1})==1
freq=varargin{1};
t=(1/freq:1/freq:length(f)/freq)';
else
t=varargin{1};
freq=1/(t(2)-t(1));
if size(t,1)==1
t=t';
end
end
cop=varargin{3};
if size(cop,1)==1
cop=cop';
f=f';
col=0;
end
else
error('Incorrect number of inputs')
return
end

%zero mean:
f=f-mean(f);
%find zeros:
[ind,xzeros]=findzeros(t,f);
xzeros=xzeros';
%pick up data between first and last zero points:
ini=floor(xzeros(1)*freq);
fim=ceil(xzeros(end)*freq);
if fim>length(t)
fim=length(t);
end
ind=[ini fim];
t=t(ini:fim);
f=f(ini:fim);
cop=cop(ini:fim);
%IEP0 & IEP:
iep0=interp1(t,cop,xzeros,'linear');
iep=interp1(xzeros,iep0,t,'spline');
%COPIEP:
copiep=cop-iep;
niep=length(xzeros)/(length(t)/freq);

varargout{1}=ind;
varargout{2}=iep;
varargout{3}=copiep;
varargout{4}=niep;
varargout{5}=xzeros;
varargout{6}=iep0;

function varargout = findzeros(varargin)
%FINDZEROS Find zeros in a vector.
% IND=FINDZEROS(Y) finds the indices (IND) which are close to local zeros in the vector Y.
% [IND,YZEROS]=FINDZEROS(X,Y), besides IND finds the values of local zeros (YZEROS) in the
% vector X by linear interpolation of the vector Y.
% Inputs:
% X: vector
% Y: vector
% Outputs:
% IND: indices of the zeros values in the vector Y
% YZEROS: values in the vector X of zeros in the vector Y
% Marcos Duarte mduarte@usp.br 11oct1998

if nargin==1
y=varargin{1};
if size(y,2)==1
y=y';
end
elseif nargin ==2
x=varargin{1};
y=varargin{2};
if ~isequal(size(x),size(y))
error('Vectors must have the same lengths')
return
elseif size(x,2)==1
x=x'; y=y';
end
else
error('Incorrect number of inputs')
return
end
% find +- transitions (approximate values for zeros):
%ind(i): the first number AFTER the zero value
ind = sort( find( ( [y 0]<0 & [0 y]>0 ) | ( [y 0]>0 & [0 y]<0 ) ) );
% find who is near zero:
ind1=find( ( abs(y(ind)) - abs(y(ind-1)) )<= 0 );
ind2=find( ( abs(y(ind)) - abs(y(ind-1)) )> 0 );
indzero = sort([ind(ind1) ind(ind2)-1 find(y==0)]);
varargout{1}=indzero;
if exist('x')
% find better approximation of zeros values using linear interpolation:
yzeros=zeros(1,length(ind));
for i=1:length(ind)
p=polyfit( y(ind(i)-1:ind(i)),x(ind(i)-1:ind(i)),1 );
yzeros(i)=polyval(p,0);
end
yzeros=sort([yzeros x(find(y==0))]);
varargout{2}=yzeros;
end

[Ivan Ramirez]

Re: rambling -trembling

thank you very much. best regards