[R] Suggestions: Terminology & Pkgs for following spectra over time

baptiste Auguié ba208 at exeter.ac.uk
Thu Apr 17 09:17:58 CEST 2008


I've found the function isPeak from the Bioconductor package  
"PROCess" very useful for peak finding. My data was similar to yours  
(spectroscopy, i'm a physicist) but not time dependent. It may be a  
starting point to work on one spectrum, retrieve a few relevant  
informations (peak positions, widths, intensities,...), and process  
similarly at regular time intervals.

< www.bioconductor.org/packages/2.0/ bioc/vignettes/PROcess/inst/doc/ 
howtoprocess.pdf  >

hope this helps,


On 17 Apr 2008, at 02:26, Bryan Hanson wrote:
> Hi Folks... No code to troubleshoot here.  I need some suggestions  
> about the
> right terminology to use in further searching, and any suggestions  
> about R
> pkgs that might be appropriate.
> I am in the planning stages of a project in which IR, NMR and other  
> spectra
> (I'm a chemist) would be collected on various samples, and individual
> samples would be followed over time.  The spectra will be feature
> rich/complex, so one can't see the changes by visual inspection.  The
> spectra are basically 2D matrices: peaks as a function of  
> frequencies.  So
> the data set is in the form of spectra of a single sample over  
> time, for
> multiple samples.
> I am wondering about methods & R pkgs that can be used to analyze  
> changes in
> the spectra over time.  For instance, I would like to find specific  
> peaks
> that are changing over time, sets of peaks that are changing in a  
> correlated
> way over time etc.  I'd like to do this in an efficient and  
> statistically
> valid way.  What I am thinking of is somewhat like a time series,  
> somewhat
> like image analysis (but only 2D), but it's not quite either of  
> those and I
> need to know what it's really called to investigate further.
> Any suggestions as to R pkgs and key words/phrases will be  
> appreciated.
> TIA, Bryan
> *************
> Bryan Hanson
> Professor of Chemistry & Biochemistry
> DePauw University, Greencastle Indiana USA
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Baptiste Auguié

Physics Department
University of Exeter
Stocker Road,
Exeter, Devon,

Phone: +44 1392 264187


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