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New Release of DSAM library, AMS and other software.

New Release of DSAM library, AMS and other software.


We would like to announce the release of the latest version of the DSAM
library, and related applications such as AMS and the new RunDSAMSim executable
function for use in Matlab/Octave .  The manual has been updated and redrafted
creating a document which is easier to read and containing more useful

The new release can be found from the 'Downloads' page at the following URL


The DSAM library has been subjected to extensive changes and improvements.  
Using the stability of the previous DSAM software as a starting point, many
subtle bugs and other problems have been weeded out.  Despite the changes,  a
great deal of effort has been made to ensure backwards compatibility with
previous simulation scripts '*.sim' and/or simulation parameter files '*.spf'. 
The new AMS application has been tested for almost a year now by a faithful
band of BETA testers. 

Improved Documentation
The manual has been redrafted.  A new layout has been introduced to increase
clarity and readability.  It now contains additional information for many of
the process modules, providing mathematical equations in the process
descriptions.  References have also been included for all published models. 
The documentation (DSAMHelp) can be installed along with AMS and other DSAM
applications and will appear as online documentation.  A PDF file will also
soon be available.

A series of tutorials is now available with the AMS application.  These
tutorials are available from the online help and provide worked examples which
help to describe AMS and how it can be used.

Simulation Scripts
Among the many new features is the enhancement of simulation scripts.  In AMS
and other DSAM applications the simulation process flow is defined using
simulations scripts.  Simulation scripts are now much less restrictive as all
process modules have default values.  This means that a simple simulation
script can be written thus:

begin {
        Stim_PureTone   # Stimulus generation.
        Trans_Ramp              # Ramp stimulus.
        Filt_BandPass   # Outer/Middle Ear filter model.
        BM_GammaT               # Basilar membrane filter model.
        IHC_Meddis86    # Hair cell model.
        Display_Signal  # Display output
        DataFile_Out    # Save output to file.


The above simulation script will run using the default value for each of the
processes.  Parameter files can be used to set the process parameters to other
value when required (or by using one of the other means of setting parameters
in DSAM applications  see the documentation).   It is also possible to
depart from the simple pipe-line simulation shown above and produce more
complex connections between processes using labels.

Free-format parameter files
The process parameter file format has also changed.  The files now consist of
free-format text files, in which each line consists of a parameter name
followed by its setting.  Only the parameters that are being changed from their
default values need to be put into the file.  Old process parameter files will
still work, though their use is deprecated.

Display Improvements
Displays produced by AMS and other DSAM applications with GUI support have been
improved.  A faster drawing algorithm has been used, that uses memory more
efficiently.  The axis scaling has also been improved, offering nicer automatic
scaling and a simple customisation method.

Threaded Operation for Applications with GUI Support
Threaded operation has been implemented for AMS and other DSAM applications
running using the graphical user inferface (GUI) support.   This means that it
is now possible to stop simulations while they are still running, without
killing the whole process.  In addition all displays will now open as soon as
their data has been generated.  This also means that you can be changing
simulation parameters while the simulation is running.

New Modules
Many new process modules have been added to the DSAM library. There are too
many to adequately list here.  Among the additions are two new complete
nonlinear AN models.  These include the 'Essex' nonlinear auditory nerve
(AN) model , including the DRNL nonlinear basilar membrane (BM) filter model
(Meddis R. Et al. 2001) and the new Meddis hair cell model ( Sumner C. Et al.
2002).  There is also the 'Boston' nonlinear AN model (Zhang X. Et al.
2001) which as an improvement of the  Carney non-linear model.

Several of the existing process modules have been enhanced, though as
previously mentioned backwards compatibility has been maintained.

Matlab 6.5 support
There is a new application, 'RunDSAMSim' which is included in the new AMS
installation. This is a DSAM application dynamically linked with Matlab 6.5,
and provides Matlab with complete control of simulations and  results.  Once
the 'RunDSAMSim.dll' file is put into the matlab path, it can then be used
in the same way as any Matlab command.   Data can be passed to and from
simulations using the function, and simulation parameters can be set.

The RunDSAMSim application can also be compiled and dynamically linked with
Octave (the freeware matlab clone).

A separte installation package has yet to be set up for the RunDSAMSim
application.  It is currently supplied with the Windows AMS installation (as
previously stated).

Adding User Modules
It is now easier for programmers to add their own modules.  Users may now
create their own modules to be used from within DSAM applications along with
the existing library process modules. Modules are generated using  the
'modgen' software tool using a simple definition file based on the process

Current developments
It will soon be possible to design simulations graphically.  A simulation
design interface (SDI) is being produced, and the development is in an advanced
stage.  The new interface will be available within a few months of the date of
this announcement, if not sooner.

New models are continually being developed and we are always happy to consider
popular models for inclusion in the DSAM library.

Important Future developments
The next major development area is the introduction of threaded processing
within DSAM.  The introduction of threading within DSAM will enable it to
better utilise today's processors (Pentium, Athlon, etc.)  Threading will also
allow DSAM to take full advantage of multi-processor systems  and the new
processors designed with increased threading in mind (incorporating
'Hyper-threading systems').

Meddis R., O'Mard L. P. & Lopez-Poveda E. A. (2001) 'A computational algorithm
for computing nonlinear auditory frequency selectivity' J. Acoust. Soc. Am.,
109: 2852-2861.

Sumner C., Lopez-Poveda E. A., O'Mard L. P. & Meddis R. (2002) 'A revised
model of the inner-hair cell and auditory-nerve complex' J. Acoust. Soc. Am.,
[111], 2178-2188.

Zhang X., Heinz M. G., Bruce, I C. & Carney L. H. (2001) 'A phenomenological
model for the responses of auditory-nerve fibers: I. Nonlinear tuning with
compression and suppression', J. Acoust. Soc. Am. [109], 648-670.
Dr. Lowel P. M. O'Mard PhD.
CNBH Essex, Dept. of Psychology,
University of Essex, Wivenhoe Park, Colchester CO4 3SQ, UK.