Charles Gatt

12-02-1998, 01:40 PM

Thanks to all who replied about determining area under the

curve with excel data. Here is a summary of responses.

Charlie Gatt

************************************************** ******************

Consult the following addresses:

MathSoft

software: Mathcad 8

www.mathsoft.com

and

Wolfram Research

software: Mathematica

www.wolfram.com

Best Regards,

Wagner de Godoy

Gait Laboratory

AACD - Brazil

www.aacd.org.br

***************************************

A couple of my PhD students have been using Kaleidagraph with success.

Yours

Liz Tanner

================================================== =========================

==

Professor K.E. Tanner

Professor of Biomedical Materials

IRC in Biomedical Materials and Department of Materials

Queen Mary and Westfield College

Mile End Road

London

E1 4NS

phone +44-171-975-5318

fax +44-181-983-1799

e-mail K.E.Tanner@qmw.ac.uk

****************************************

I suppose, that you have a certain number of points (lets say n pairs

(x_i,y_i)) which define your curve. The integral is then defined as

I = sum( (y_(i+1) + y_i )/2 * ( x_(i+1) - x_i )

where the sum runs over all points i=1,...,n-1. You should be able to

define this in Excel yourself.

Regards

Martin

--

__________________________________________________ _________________________

____________

Dr. Martin Pohl

Department of Orthopaedic Research and Biomechanics

Helmholtzstr. 14

89081 ULM

Germany, EU

phone: +49-(0)731-50-23494 FAX: +49-(0)731-50-23498

WWW: http://pollux.medizin.uni-ulm.de e-mail:

mailto://martin.pohl@medizin.uni-ulm.de

************************************************** ***************

There is a software which you can download free

it is called accuROC.

Chaim Singal

************************************************** **************

Easy, have you got student edition of MATLAB. If so use Trapz function.

Import x,y series as cols. into matlab using LOAD function.

N.B. You dont even have to import x series, as long as you know the

difference between x1,x2 (and it is constant, like time) etc then multiply

the output of Trapz function by (x2-x1). Do it for each series.

One problem though, make sure all col. are of sam length as MATLAB imports

as a matrix (access each col. of matrix in turn). Solution, replace empty

cells with zeros.

Simple, I hope. Any questions I had to do this recently. Takes only a few

minutes.

Regards

William Higgs

Mechanical Engineering

University of Sydney

Australia

************************************************** ***********

Just look in any introductory calculus textbook for calculations of

areas under curves. You could use the trapezoidal approximation,

Simpson's rule or any other approach. You just calculate the formula

for two or three cells and copy it down the column. Dead easy.

Best regards,

Mike

J. Michael Lee, Ph.D.

Interim Director, Biomedical Engineering Programme

Associate Professor of Biomaterials (902) 494-6734 (Voice)

Chair, Dept. of Applied Oral Sciences (902) 494-2527 (FAX)

Dalhousie University

5981 University Avenue jmlee@is.dal.ca

Halifax, Nova Scotia (902) 494-2162 Tissue Mechanics Lab

Canada B3H 3J5 (902) 494-6784 Tissue Structure Lab

************************************************** ***********

BioProc - Software for processing of analog data (contributed by Gordon ERobertson) reads and displays Kistler, APAS and other file formats.

Includes algorithms for smoothing and ensemble averaging of signals.

This program is designed to perform many types of processing on data or

various data or properly formatted ASCII files. There are many different

ways of integrating in this program, and choosing the most appropriate

depends on the type of data being used.

You can download this software from the ISB website. Also, you can download

the Bioproc manual. Follow the instructions for installation from the ISB

website. Lastly, you most likely will have to convert your ascii files into

*.bpa format which will enable Bioproc to read and process you files. This

is freeware software so you can't go wrong. I use this software for

processing GRF forces, EMG data and any sort of other data. It is quite a

powerful tool in your software arsenal.

Dan

Dan Ramsey

Motor Control Laboratory Tel: +46 (8)-517-77-503

Astrid Lindgren Hospital Fax: +46 (8)-517-77-351

Karolinska Institute E-mail: Dan.Ramsey@kbh.ki.se

S-171 76 Stockholm

Sweden

Motorlab Homepage: http://ikaros.f1.ki.se/motorlab/index.htm

Faculty Homepage: http://137.122.122.109/

************************************************** ***********

You can write your own macro to estimate area using something like a

trapezoidal estimation. Here is the code I use in C (you can adapt it as

you like).

/* trapezoidal approximation */

float t=0;

flg=5;

Fs=input("Enter the Frame rate, OR enter -1 if you prefer to

provide

interval time: ");

if(Fs==-1) {

t=input("Enter interval time: "); }

else {

t=1/Fs;

printf("\nInterval time is %1.5f",t); }

for(i=0; i

curve with excel data. Here is a summary of responses.

Charlie Gatt

************************************************** ******************

Consult the following addresses:

MathSoft

software: Mathcad 8

www.mathsoft.com

and

Wolfram Research

software: Mathematica

www.wolfram.com

Best Regards,

Wagner de Godoy

Gait Laboratory

AACD - Brazil

www.aacd.org.br

***************************************

A couple of my PhD students have been using Kaleidagraph with success.

Yours

Liz Tanner

================================================== =========================

==

Professor K.E. Tanner

Professor of Biomedical Materials

IRC in Biomedical Materials and Department of Materials

Queen Mary and Westfield College

Mile End Road

London

E1 4NS

phone +44-171-975-5318

fax +44-181-983-1799

e-mail K.E.Tanner@qmw.ac.uk

****************************************

I suppose, that you have a certain number of points (lets say n pairs

(x_i,y_i)) which define your curve. The integral is then defined as

I = sum( (y_(i+1) + y_i )/2 * ( x_(i+1) - x_i )

where the sum runs over all points i=1,...,n-1. You should be able to

define this in Excel yourself.

Regards

Martin

--

__________________________________________________ _________________________

____________

Dr. Martin Pohl

Department of Orthopaedic Research and Biomechanics

Helmholtzstr. 14

89081 ULM

Germany, EU

phone: +49-(0)731-50-23494 FAX: +49-(0)731-50-23498

WWW: http://pollux.medizin.uni-ulm.de e-mail:

mailto://martin.pohl@medizin.uni-ulm.de

************************************************** ***************

There is a software which you can download free

it is called accuROC.

Chaim Singal

************************************************** **************

Easy, have you got student edition of MATLAB. If so use Trapz function.

Import x,y series as cols. into matlab using LOAD function.

N.B. You dont even have to import x series, as long as you know the

difference between x1,x2 (and it is constant, like time) etc then multiply

the output of Trapz function by (x2-x1). Do it for each series.

One problem though, make sure all col. are of sam length as MATLAB imports

as a matrix (access each col. of matrix in turn). Solution, replace empty

cells with zeros.

Simple, I hope. Any questions I had to do this recently. Takes only a few

minutes.

Regards

William Higgs

Mechanical Engineering

University of Sydney

Australia

************************************************** ***********

Just look in any introductory calculus textbook for calculations of

areas under curves. You could use the trapezoidal approximation,

Simpson's rule or any other approach. You just calculate the formula

for two or three cells and copy it down the column. Dead easy.

Best regards,

Mike

J. Michael Lee, Ph.D.

Interim Director, Biomedical Engineering Programme

Associate Professor of Biomaterials (902) 494-6734 (Voice)

Chair, Dept. of Applied Oral Sciences (902) 494-2527 (FAX)

Dalhousie University

5981 University Avenue jmlee@is.dal.ca

Halifax, Nova Scotia (902) 494-2162 Tissue Mechanics Lab

Canada B3H 3J5 (902) 494-6784 Tissue Structure Lab

************************************************** ***********

BioProc - Software for processing of analog data (contributed by Gordon ERobertson) reads and displays Kistler, APAS and other file formats.

Includes algorithms for smoothing and ensemble averaging of signals.

This program is designed to perform many types of processing on data or

various data or properly formatted ASCII files. There are many different

ways of integrating in this program, and choosing the most appropriate

depends on the type of data being used.

You can download this software from the ISB website. Also, you can download

the Bioproc manual. Follow the instructions for installation from the ISB

website. Lastly, you most likely will have to convert your ascii files into

*.bpa format which will enable Bioproc to read and process you files. This

is freeware software so you can't go wrong. I use this software for

processing GRF forces, EMG data and any sort of other data. It is quite a

powerful tool in your software arsenal.

Dan

Dan Ramsey

Motor Control Laboratory Tel: +46 (8)-517-77-503

Astrid Lindgren Hospital Fax: +46 (8)-517-77-351

Karolinska Institute E-mail: Dan.Ramsey@kbh.ki.se

S-171 76 Stockholm

Sweden

Motorlab Homepage: http://ikaros.f1.ki.se/motorlab/index.htm

Faculty Homepage: http://137.122.122.109/

************************************************** ***********

You can write your own macro to estimate area using something like a

trapezoidal estimation. Here is the code I use in C (you can adapt it as

you like).

/* trapezoidal approximation */

float t=0;

flg=5;

Fs=input("Enter the Frame rate, OR enter -1 if you prefer to

provide

interval time: ");

if(Fs==-1) {

t=input("Enter interval time: "); }

else {

t=1/Fs;

printf("\nInterval time is %1.5f",t); }

for(i=0; i