Newsgroup: it.hobby.hi-fi
Titolo: Annuncio trovato su altro n.g.

Leggo e riferisco quanto reperito sul newsgroup "comp.ai.neural-nets".
Commenti benvenuti, con l'avvertenza che ambasciatore non porta pena.
--Stefano Rovetta
s...@dibe.unige.it
Source:   Boston University (
http://www.bu.edu/
)
Date:   Posted 9/7/99
Biologically Inspired Electronics Leads To Higher Fidelity
Boston University researchers base noise-shaping technology on neuronal
networks
(Boston, Mass.) - The human brain is the most elegant of receivers. It can
discern the notes of a piccolo from amongst the multitude of tones in a
symphony orchestra and identify the familiar outlines of a friend in the
midst of a crowd of strangers.
Realizing this extraordinary ability of the neuronal networks of the brain
to separate signal from noise led a group of researchers at Boston
University's Center for BioDynamics (CBD) and Department of Biomedical
Engineering to develop a biologically inspired model that would improve the
fidelity of electronic devices. The work was supported by a research gift
from Ray Stata, chairman of Analog Devices and conducted in collaboration
with Carson Chow (University of Pittsburgh), Wulfram Gerstner (Swiss Federal
Institute of Technology), and Robert W. Adams, (manager of audio development
at Analog Devices, Inc. of Norwood, Mass.), who first suggested the concept.
It is reported in the August 31 issue of the Proceedings of the National
Academy of Sciences.
Spectral noise-shaping, a process by which engineers improve the
signal-to-noise ratio in electronic systems, is used in audio applications
such as digital telephones, theater sound systems, and CD players.
Traditional noise-shaping relies upon digital averaging techniques that are
effective only in a narrow range of frequencies.
The techniques developed by Douglas Mar, James Collins, and their colleagues
have significant advantages in that they can be effective over a much wider
bandwidth, and can tolerate a greater amount of variation in the system
components. The system is based on large networks of interconnected
circuits, similar to neuronal networks in the brain. It is known that
neurons fire in an often noisy and irregular pattern in the brain. Also,
neurons often fire slowly in comparison to many of the signals they need to
encode - a pitched baseball, for example, is in the "hitting zone" for only
a few milliseconds, whereas individual neurons often take ten milliseconds
or more between firings. Despite this discrepancy in timing, major leaguers
such as Mark McGwire and Sammy Sosa hit home runs regularly.
The researchers hypothesized that a more efficient flow of information is
effected in neuronal networks by inhibitory coupling - a process through
which activation of one neuron momentarily suppresses the level of activity
in other neurons in the network. Inhibitory coupling reduces the clumping of
information, avoiding information traffic jams that both make it difficult
to "see" the information of interest and slow down the system. By connecting
elements in this way the researchers were able to similarly smooth the flow
of information and identify and shift the noise, or unwanted information,
from the bandwidth of interest to higher frequencies where it can be
filtered out.
The next step, according to Mar, is to take the theoretical results of this
investigation and begin to apply it in actual devices to bring higher
fidelity into a new generation of biologically inspired electronics.
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----
Note: This story has been adapted from a news release issued by Boston
University for journalists and other members of the public. If you wish to
quote from any part of this story, please credit Boston University as the
original source. You may also wish to include the following link in any
citation:
http://www.sciencedaily.com/releases/1999/09/990907072721.htm

midst of a crowd of strangers.
Molto interessante, ma non dimentichiamo che certe cose  il cervello
se le inventa.....(leggi allucinazioni, sonore o visive che siano).
Ciao.
Francesco...@PROselin.com
P.S. : E cosě abbiamo accontentato anche gli "strumentisti" ad
oltranza.

La notizia è interessante, sopratutto le conclusioni, perchè almeno
qualcuno comincia ad interrogarsi seriamente su questi problemi, ma
anche scontata, in quanto queste cose fanno parte del bagaglio
"neuronale" di chiunque ascolti musica dal vivo e abbia la voglia e
capacità di fare qualche prova senza piantare i piedi a mò di ciucco
quando non capisce qualcosa :-)
ciao
Ruggero