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mlpack/fastlib/u/nvasil/docs/proposal/summary.tex
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\documentclass[12pt]{article}
\begin{document}
\pagestyle{plain}
\begin{center}
\textbf{Proposal Summary}
\end{center}
\textbf{Goal:} Compute the intrinsic dimension of several speech
representations. Fast computation for kernel matrix. Fast
optimization of the kernel matrix. Nearest neighbor speech
recognition.
\textbf{Contributions:}
\begin{enumerate}
\item Fast computation for kernel matrix.
\item Fast optimization of the kernel matrix.
\item On-line kernel adaptive filters.
\end{enumerate}
\textbf{Specific tasks (Done):}
\begin{enumerate}
\item \textit{The Nearest Neighbor Problem} Approached the problem
with trees that give the exact nearest neighbor. We could have also
considered the approximate nearest neighbor problem that can be
solved with other methods. But still trees is the best approach
and also it is not yet known whether approximate nearest neighbor
gives better performance.
\item \textit{Multidimensional Trees} Studied developed and
optimized kd-trees and ball trees. We didn't consider other types
since comparative study has shown that they are still the state of
the art.
\item \textit{All nearest Neighbors} Implemented the best
algorithm (dual tree) algorithm.
\item \textit{Large scale trees, for out of core memory} Followed
different caching practices for trees that don't fit in the main
memory. Optimized code. Showed that the dual tree algorithm has
very good locality structure.
\item \textit{Fast k-nearest neighbor kernel computation} It is
based on direct application of the all-nearest neighbor algorithm
\item \textit{tuning the kernel bandwidth} Developed and algorithm
for tuning non-parametrically the gaussian kernel in spectral
clustering algorithms such as kernel-pca and diffusion mapping
\item \textit{Phoneme classification with nearest neighbor
classifier} Experimented with MFCC and NRAF features on the whole
TIMIT database and managed to get up to 60\% correct phoneme
classification only by looking at the nearest neighbor. The method
can scale up linearly.
\end{enumerate}
\textbf{Specific tasks (To do):}
\begin{enumerate}
\item \textit{Customizing Kernels with semidefinite programming}
There is an existing method for optimizing the kernel matrix based
on semidefinite programming. There are certain optimizations that
can be done along with the dual tree algorithm for linear scaling,
such as application of stochastic optimization
\item \textit{Fast kernel summation with trees, Kernel Matrix
inversion} Direct computation of the kernel(Gaussian) kernel leads
to a non-sparse matrix. There is a way though to compute the
inverse/eigenvalues without explicitly computing the kernel
matrix. Several optimizations can be done for high dimensions
\item \textit{Speech recognition with nearest neighbor search}
Implement a merge reduce scheme to create different descriptions
of speech. Use nearest neighbor algorithms to replace gaussian
mixtures in hidden markov models.
\item \textit{Parallelize the code to handle larger datasets} The
goal is to measure the intrinsic dimension of the broadcast news
dataset. Test it with fast gaussian summation and with optimized
kernels.
\end{enumerate}
\end{document}