comparison draft.tex @ 24:79ede31feb20

Stuffed a load more figures in.
author samer
date Tue, 13 Mar 2012 11:28:02 +0000
parents f9a67e19a66b
children 3f08d18c65ce
comparison
equal deleted inserted replaced
23:f9a67e19a66b 24:79ede31feb20
13 \usetikzlibrary{matrix} 13 \usetikzlibrary{matrix}
14 \usetikzlibrary{patterns} 14 \usetikzlibrary{patterns}
15 \usetikzlibrary{arrows} 15 \usetikzlibrary{arrows}
16 16
17 \let\citep=\cite 17 \let\citep=\cite
18 \newcommand{\colfig}[2][1]{\includegraphics[width=#1\linewidth]{figs/#2}}% 18 \newcommand{\colfig}[2][1]{\includegraphics[width=#1\linewidth]{ifigs/#2}}%
19 \newcommand\preals{\reals_+} 19 \newcommand\preals{\reals_+}
20 \newcommand\X{\mathcal{X}} 20 \newcommand\X{\mathcal{X}}
21 \newcommand\Y{\mathcal{Y}} 21 \newcommand\Y{\mathcal{Y}}
22 \newcommand\domS{\mathcal{S}} 22 \newcommand\domS{\mathcal{S}}
23 \newcommand\A{\mathcal{A}} 23 \newcommand\A{\mathcal{A}}
108 degrees of belief about the various proposition which may or may not 108 degrees of belief about the various proposition which may or may not
109 hold, and, as has been argued elsewhere \cite{Cox1946,Jaynes27}, best 109 hold, and, as has been argued elsewhere \cite{Cox1946,Jaynes27}, best
110 quantified in terms of Bayesian probability theory. 110 quantified in terms of Bayesian probability theory.
111 Thus, we suppose that 111 Thus, we suppose that
112 when we listen to music, expectations are created on the basis of our 112 when we listen to music, expectations are created on the basis of our
113 familiarity with various stylistic norms %, that is, using models that 113 familiarity with various stylistic norms that apply to music in general,
114 encode the statistics of music in general, the particular styles of 114 the particular style (or styles) of music that seem best to fit the piece
115 music that seem best to fit the piece we happen to be listening to, and 115 we are listening to, and
116 the emerging structures peculiar to the current piece. There is 116 the emerging structures peculiar to the current piece. There is
117 experimental evidence that human listeners are able to internalise 117 experimental evidence that human listeners are able to internalise
118 statistical knowledge about musical structure, \eg 118 statistical knowledge about musical structure, \eg
119 \citep{SaffranJohnsonAslin1999,EerolaToiviainenKrumhansl2002}, and also 119 \citep{SaffranJohnsonAslin1999,EerolaToiviainenKrumhansl2002}, and also
120 that statistical models can form an effective basis for computational 120 that statistical models can form an effective basis for computational
121 analysis of music, \eg 121 analysis of music, \eg
122 \cite{ConklinWitten95,PonsfordWigginsMellish1999,Pearce2005}. 122 \cite{ConklinWitten95,PonsfordWigginsMellish1999,Pearce2005}.
123 123
124 \subsection{Music and information theory} 124 \subsection{Music and information theory}
125 Given a probabilistic framework for music modelling and prediction, 125 With a probabilistic framework for music modelling and prediction in hand,
126 it is a small step to apply quantitative information theory \cite{Shannon48} to 126 we are in a position to apply quantitative information theory \cite{Shannon48}.
127 the models at hand.
128 The relationship between information theory and music and art in general has been the 127 The relationship between information theory and music and art in general has been the
129 subject of some interest since the 1950s 128 subject of some interest since the 1950s
130 \cite{Youngblood58,CoonsKraehenbuehl1958,HillerBean66,Moles66,Meyer67,Cohen1962}. 129 \cite{Youngblood58,CoonsKraehenbuehl1958,HillerBean66,Moles66,Meyer67,Cohen1962}.
131 The general thesis is that perceptible qualities and subjective 130 The general thesis is that perceptible qualities and subjective
132 states like uncertainty, surprise, complexity, tension, and interestingness 131 states like uncertainty, surprise, complexity, tension, and interestingness
154 with `low entropy'. These values were determined from some known `objective' 153 with `low entropy'. These values were determined from some known `objective'
155 probability model of the stimuli,% 154 probability model of the stimuli,%
156 \footnote{% 155 \footnote{%
157 The notion of objective probabalities and whether or not they can 156 The notion of objective probabalities and whether or not they can
158 usefully be said to exist is the subject of some debate, with advocates of 157 usefully be said to exist is the subject of some debate, with advocates of
159 subjective probabilities including de Finetti \cite{deFinetti}. 158 subjective probabilities including de Finetti \cite{deFinetti}.}
160 Accordingly, we will treat the concept of a `true' or `objective' probability
161 models with a grain of salt and not rely on them in our
162 theoretical development.}%
163 or from simple statistical analyses such as 159 or from simple statistical analyses such as
164 computing emprical distributions. Our approach is explicitly to consider the role 160 computing emprical distributions. Our approach is explicitly to consider the role
165 of the observer in perception, and more specifically, to consider estimates of 161 of the observer in perception, and more specifically, to consider estimates of
166 entropy \etc with respect to \emph{subjective} probabilities. 162 entropy \etc with respect to \emph{subjective} probabilities.
167 \subsection{Information dynamic approach} 163 \subsection{Information dynamic approach}
168 164
169 Bringing the various strands together, our working hypothesis is that 165 Bringing the various strands together, our working hypothesis is that as a
170 as a listener (to which will refer gender neutrally as `it') 166 listener (to which will refer as `it') listens to a piece of music, it maintains
171 listens to a piece of music, it maintains a dynamically evolving statistical 167 a dynamically evolving statistical model that enables it to make predictions
172 model that enables it to make predictions about how the piece will 168 about how the piece will continue, relying on both its previous experience
173 continue, relying on both its previous experience of music and the immediate 169 of music and the immediate context of the piece. As events unfold, it revises
174 context of the piece. 170 its model and hence its probabilistic belief state, which includes predictive
175 As events unfold, it revises its model and hence its probabilistic belief state, 171 distributions over future observations. These distributions and changes in
176 which includes predictive distributions over future observations. 172 distributions can be characterised in terms of a handful of information
177 These distributions and changes in distributions can be characterised in terms of a handful of information 173 theoretic-measures such as entropy and relative entropy. By tracing the
178 theoretic-measures such as entropy and relative entropy. 174 evolution of a these measures, we obtain a representation which captures much
179 % to measure uncertainty and information. %, that is, changes in predictive distributions maintained by the model. 175 of the significant structure of the music, but does so at a high level of
180 By tracing the evolution of a these measures, we obtain a representation 176 \emph{abstraction}, since it is sensitive mainly to \emph{patterns} of occurence,
181 which captures much of the significant structure of the 177 rather the details of which specific things occur or even the sensory modality
182 music. 178 through which they are detected. This suggests that the
183 This approach has a number of features which we list below.
184
185 \emph{Abstraction}:
186 Because it is sensitive mainly to \emph{patterns} of occurence,
187 rather the details of which specific things occur,
188 it operates at a level of abstraction removed from the details of the sensory
189 experience and the medium through which it was received, suggesting that the
190 same approach could, in principle, be used to analyse and compare information 179 same approach could, in principle, be used to analyse and compare information
191 flow in different temporal media regardless of whether they are auditory, 180 flow in different temporal media regardless of whether they are auditory,
192 visual or otherwise. 181 visual or otherwise.
193 182
194 \emph{Generality} applicable to any probabilistic model. 183 In addition, the information dynamic approach gives us a principled way
195 184 to address the notion of \emph{subjectivity}, since the analysis is dependent on the
196 \emph{Subjectivity}: 185 probability model the observer starts off with, which may depend on prior experience
197 Since the analysis is dependent on the probability model the observer brings to the 186 or other factors, and which may change over time. Thus, inter-subject variablity and
198 problem, which may depend on prior experience or other factors, and which may change 187 variation in subjects' responses over time are
199 over time, inter-subject variablity and variation in subjects' responses over time are 188 fundamental to the theory.
200 fundamental to the theory. It is essentially a theory of subjective response
201 189
202 %modelling the creative process, which often alternates between generative 190 %modelling the creative process, which often alternates between generative
203 %and selective or evaluative phases \cite{Boden1990}, and would have 191 %and selective or evaluative phases \cite{Boden1990}, and would have
204 %applications in tools for computer aided composition. 192 %applications in tools for computer aided composition.
205 193
206 194
207 \section{Theoretical review} 195 \section{Theoretical review}
208 196
197 \subsection{Entropy and information in sequences}
209 In this section, we summarise the definitions of some of the relevant quantities 198 In this section, we summarise the definitions of some of the relevant quantities
210 in information dynamics and show how they can be computed in some simple probabilistic 199 in information dynamics and show how they can be computed in some simple probabilistic
211 models (namely, first and higher-order Markov chains, and Gaussian processes [Peter?]). 200 models (namely, first and higher-order Markov chains, and Gaussian processes [Peter?]).
212 201
213 \begin{fig}{venn-example} 202 \begin{fig}{venn-example}
278 I_{12|3} + I_{123} &= I(X_1;X_2) 267 I_{12|3} + I_{123} &= I(X_1;X_2)
279 \end{align*} 268 \end{align*}
280 } 269 }
281 \end{tabular} 270 \end{tabular}
282 \caption{ 271 \caption{
283 Venn diagram visualisation of entropies and mutual informations 272 Information diagram visualisation of entropies and mutual informations
284 for three random variables $X_1$, $X_2$ and $X_3$. The areas of 273 for three random variables $X_1$, $X_2$ and $X_3$. The areas of
285 the three circles represent $H(X_1)$, $H(X_2)$ and $H(X_3)$ respectively. 274 the three circles represent $H(X_1)$, $H(X_2)$ and $H(X_3)$ respectively.
286 The total shaded area is the joint entropy $H(X_1,X_2,X_3)$. 275 The total shaded area is the joint entropy $H(X_1,X_2,X_3)$.
287 The central area $I_{123}$ is the co-information \cite{McGill1954}. 276 The central area $I_{123}$ is the co-information \cite{McGill1954}.
288 Some other information measures are indicated in the legend. 277 Some other information measures are indicated in the legend.
429 the entropy rate and the erasure entropy rate: $b_\mu = h_\mu - r_\mu$. 418 the entropy rate and the erasure entropy rate: $b_\mu = h_\mu - r_\mu$.
430 These relationships are illustrated in \Figrf{predinfo-bg}, along with 419 These relationships are illustrated in \Figrf{predinfo-bg}, along with
431 several of the information measures we have discussed so far. 420 several of the information measures we have discussed so far.
432 421
433 422
423 \begin{fig}{wundt}
424 \raisebox{-4em}{\colfig[0.43]{wundt}}
425 % {\ \shortstack{{\Large$\longrightarrow$}\\ {\scriptsize\emph{exposure}}}\ }
426 {\ {\large$\longrightarrow$}\ }
427 \raisebox{-4em}{\colfig[0.43]{wundt2}}
428 \caption{
429 The Wundt curve relating randomness/complexity with
430 perceived value. Repeated exposure sometimes results
431 in a move to the left along the curve \cite{Berlyne71}.
432 }
433 \end{fig}
434
435
434 \subsection{First order Markov chains} 436 \subsection{First order Markov chains}
435 These are the simplest non-trivial models to which information dynamics methods 437 These are the simplest non-trivial models to which information dynamics methods
436 can be applied. In \cite{AbdallahPlumbley2009} we, showed that the predictive information 438 can be applied. In \cite{AbdallahPlumbley2009} we, showed that the predictive information
437 rate can be expressed simply in terms of the entropy rate of the Markov chain. 439 rate can be expressed simply in terms of the entropy rate of the Markov chain.
438 If we let $a$ denote the transition matrix of the Markov chain, and $h_a$ it's 440 If we let $a$ denote the transition matrix of the Markov chain, and $h_a$ it's
462 \section{Information Dynamics in Analysis} 464 \section{Information Dynamics in Analysis}
463 465
464 \subsection{Musicological Analysis} 466 \subsection{Musicological Analysis}
465 refer to the work with the analysis of minimalist pieces 467 refer to the work with the analysis of minimalist pieces
466 468
469 \begin{fig}{twopages}
470 % \colfig[0.96]{matbase/fig9471} % update from mbc paper
471 \colfig[0.97]{matbase/fig72663}\\ % later update from mbc paper (Keith's new picks)
472 \vspace*{1em}
473 \colfig[0.97]{matbase/fig13377} % rule based analysis
474 \caption{Analysis of \emph{Two Pages}.
475 The thick vertical lines are the part boundaries as indicated in
476 the score by the composer.
477 The thin grey lines
478 indicate changes in the melodic `figures' of which the piece is
479 constructed. In the `model information rate' panel, the black asterisks
480 mark the
481 six most surprising moments selected by Keith Potter.
482 The bottom panel shows a rule-based boundary strength analysis computed
483 using Cambouropoulos' LBDM.
484 All information measures are in nats and time is in notes.
485 }
486 \end{fig}
487
488 \begin{fig}{metre}
489 \scalebox{1}[0.8]{%
490 \begin{tabular}{cc}
491 \colfig[0.45]{matbase/fig36859} & \colfig[0.45]{matbase/fig88658} \\
492 \colfig[0.45]{matbase/fig48061} & \colfig[0.45]{matbase/fig46367} \\
493 \colfig[0.45]{matbase/fig99042} & \colfig[0.45]{matbase/fig87490}
494 % \colfig[0.46]{matbase/fig56807} & \colfig[0.48]{matbase/fig27144} \\
495 % \colfig[0.46]{matbase/fig87574} & \colfig[0.48]{matbase/fig13651} \\
496 % \colfig[0.44]{matbase/fig19913} & \colfig[0.46]{matbase/fig66144} \\
497 % \colfig[0.48]{matbase/fig73098} & \colfig[0.48]{matbase/fig57141} \\
498 % \colfig[0.48]{matbase/fig25703} & \colfig[0.48]{matbase/fig72080} \\
499 % \colfig[0.48]{matbase/fig9142} & \colfig[0.48]{matbase/fig27751}
500
501 \end{tabular}%
502 }
503 \caption{Metrical analysis by computing average surprisingness and
504 informative of notes at different periodicities (\ie hypothetical
505 bar lengths) and phases (\ie positions within a bar).
506 }
507 \end{fig}
508
467 \subsection{Content analysis/Sound Categorisation}. 509 \subsection{Content analysis/Sound Categorisation}.
468 Using Information Dynamics it is possible to segment music. From there we 510 Using Information Dynamics it is possible to segment music. From there we
469 can then use this to search large data sets. Determine musical structure for 511 can then use this to search large data sets. Determine musical structure for
470 the purpose of playlist navigation and search. 512 the purpose of playlist navigation and search.
471 \emph{Peter} 513 \emph{Peter}
472 514
473 \subsection{Beat Tracking} 515 \subsection{Beat Tracking}
474 \emph{Andrew} 516 \emph{Andrew}
475 517
476 518
477 \section{Information Dynamics as Design Tool} 519 \section{Information dynamics as compositional aid}
478 520
479 In addition to applying information dynamics to analysis, it is also possible 521 In addition to applying information dynamics to analysis, it is also possible
480 use this approach in design, such as the composition of musical materials. By 522 use this approach in design, such as the composition of musical materials. By
481 providing a framework for linking information theoretic measures to the control 523 providing a framework for linking information theoretic measures to the control
482 of generative processes, it becomes possible to steer the output of these processes 524 of generative processes, it becomes possible to steer the output of these processes
539 triangle, the corresponding transition matrix is returned. Figure \ref{TheTriangle} 581 triangle, the corresponding transition matrix is returned. Figure \ref{TheTriangle}
540 shows how the triangle maps to different measures of redundancy, entropy rate 582 shows how the triangle maps to different measures of redundancy, entropy rate
541 and predictive information rate.\emph{self-plagiarised} 583 and predictive information rate.\emph{self-plagiarised}
542 \begin{figure} 584 \begin{figure}
543 \centering 585 \centering
544 \includegraphics[width=\linewidth]{figs/TheTriangle.pdf} 586 \includegraphics[width=0.85\linewidth]{figs/TheTriangle.pdf}
545 \caption{The Melody Triangle\label{TheTriangle}} 587 \caption{The Melody Triangle\label{TheTriangle}}
546 \end{figure} 588 \end{figure}
547 Each corner corresponds to three different extremes of predictability and 589 Each corner corresponds to three different extremes of predictability and
548 unpredictability, which could be loosely characterised as `periodicity', `noise' 590 unpredictability, which could be loosely characterised as `periodicity', `noise'
549 and `repetition'. Melodies from the `noise' corner have no discernible pattern; 591 and `repetition'. Melodies from the `noise' corner have no discernible pattern;