Re: robot com-posers


Subject: Re: robot com-posers
From: Philippe-Aubert Gauthier (Philippe-Aubert.Gauthier@USherbrooke.ca)
Date: Thu Feb 17 2005 - 12:14:26 EST


CIRMMT is pleased to announce a guest lecture by Godfried Toussaint,
Professor in the School of Computer Science at McGill University.

Date: Friday, February 18, 2005
Time: 3:30pm
Location: Strathcona Music Building, 555 Sherbrooke St. West, Clara
Lichtenstein Recital Hall (C-209)
Title: Computational Methods for the Analysis and Generation of Musical
Rhythm Timelines

Abstract:
Computational methods for the analysis and generation of rhythm timelines
are described. Mathematical measures of rhythm preference are compared.
Several methods for representing rhythm, and for measuring rhythm
similarity, are reviewed. Tools from bioinformatics are used to perform
phylogenetic analyses of families of rhythms that are common in African and
Afro-American music. Several computational open problems related to the
problems mentioned above as well as the "reconstruction" of "ancestral"
rhythms are outlined.

Selon Kevin Austin <kevin.austin@videotron.ca>:

>
> I think this is a slight simplification and obscures some basic
> elements that are making research difficult.
>
> One could talk about the "stream of data", and how to deal with it.
> Adopting the ASA terms, the first thing to be done is to somehow
> 'segment' the data -- it has to be taken in 'chunks'. With a message
> like:
>
> 00111010010010111010010101001001110100101001010010101111011101010100
> 01001000101111010101101010101001010101001011010101010100101010001011
> 11111010011010010010110100101001001001001010111110100100010000001010
>
> The individual digits reveal (almost) nothing. One needs to determine
> where the 'meaningful segmentation' is. In written language, this is
> shown by spaces. The segmentation can evan allouw errers tu cum inta
> thur streem anits pozible te figur ou wots bein rittern, but without
> the segmentation markers ...
>
> thaholldamtingizsamushhmahdifelultergittaideeoffaztsgoawnaughtbeesaez.
>
> Eliot's work (and those who start from MIDI as being 'music') accept
> that the segmentation occurs at the level of the "note". Ea composers
> live in the sub-particle world as well.
>
> Voice recognition has come a long way, when the source is 'clean',
> but if there is background noise, or another voice present, there is
> the much more complex problem of sorting out whether and "chunk" of
> sound is "integrated" or requires "segregation". A bell with a
> complex harmonic spectra 'functions' as an integrated sound, as do
> the low notes of the piano.
>
> Here is a little text to demonstrate the problem ... you need to
> figure out whether there are two different texts (such as two
> voices), or one text with noise ... (in which case one works to
> eliminate the noise -- a kind of karaoke in reverse).
>
>
> ThThiDissisisiz inisen fconfacact ttohred te teexxdets tht hat
> afistrs b heeave betin cerst ton nl putgethhded ioed witser wierrers
> aex siikento tth the texts nd its r chooo usons ofen sube melhe chch
> thamoget esen tplit thenuf letxt we ter epeet s and tth da choz. reed
> toein texopehe fexcarry lots citittsa repiaen nrry repeot ttitions of
> letlettters. eets ers.
>
> (* see bottom)
>
> Given english language frequency tables you can probably figure out
> that this is not a standard english, but possible is something about
> "text", due to the frequency of the "ex" and "xt" combinations, and
> towards the end the ideas of "repetition" and "letters" begin to
> emerge as one moves to third and fourth order Markov chains. The
> first string seems to contain elements of "This" ties to "is"
> followed by "in" and "fact", and at this stage, the Markov chains
> work at the level of syntax ... something like ... "This is in fact
> ..." "text" ... "choose ..?" ... "text" ... "repeat" etc etc
>
> But this depends upon a prior knowledge of several aspects of the
> language involved, both at the vocabulary and syntax levels. This has
> required the development of a relatively robust theory ... one which
> is able to describe large portions of the existing body of material,
> and that can be somewhat predictive of what is 'possible' within the
> 'core' of the language.
>
> A sense of this can be found in looking at English as Second Language
> dictionaries, where 10,000 english words are defined, but the reader
> needs to know only 2,000 words, and all of the words are defined with
> the restricted vocabulary of the 2,000 'core' words.
>
> For tonal music, there are only a handful of 'core' rules related to
> the Circle of Fifths and 'scale degree resolution'.
>
> Vocabulary segmentation (using the note and MIDI model) is not a
> major issue. The (metric) model also proposes standardized ways of
> generating vocabulary groupings (derived from concepts of harmonic
> rhythm), and these concepts can start to generate basic 'core'
> analyses that work for over 90% of western music from 1600 - 1870.
>
> But, this doesn't work on the 'sound', which is a large part of the
> work in ASA and psychoacoustics in general. Given the central role of
> the individual's central processing (brain and/or mind), in ea, it
> seems that a solid introduction to psychoacoustics is important in
> the field of electroacoustic studies.
>
> One does not seriously study the literature of western music without
> a firm grounding in notation and concepts of meter, harmony (figured
> bass, chords and progressions), and their interaction in melody and
> counterpoint.
>
> Often hypothetical or "what-if" scenarios are introduced, but the
> question I raise (and delimit) is one of the practice as reflected in
> the work of hundred of thousands of people, not in the musings of an
> individual (even if it is Cowell, Partch or Stockhausen).
>
> My consideration here is not about "possible" musics, but about
> exiting practice.
>
> Best
>
> Kevin
>
>
> (* texts)
> (1) This is in fact three texts that have been put together with the
> texts chosen such that the texts carry repetitions of letters.
> (2) This second text has been chosen not too unlike the first to be
> melded into the chosen text with repetitions of letters.
> (3) Dis iz infac de firs tex simplied wit errers and its repeeted too
> get enuf letters and da chozein tex carry lotsa repeets.
>
>
>
>
>
> At 18:19 -0500 2005/02/16, n_kondon@alcor.concordia.ca wrote:
> >Can you tech a computer to recognise patterns? It has been done for
> >speech/writing to a certain degree.
>
>
>
>

%====================================================================%
% Philippe-Aubert Gauthier, B.Ing, M.Sc. %
% Étudiant au doctorat en reproduction de champs acoustiques %
% %
% GAUS (Groupe d'Acoustique et de vibrations de l'Université de %
% [ Sherbrooke) %
% CIRMMT (Centre for Interdisciplinary research in Music, Media %
% [ and Technology) %
% %
% http://www3.sympatico.ca/philippe_aubert_gauthier/acoustics.html %
%====================================================================%



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